MSc (Biochemistry) / Department of Biochemistry / Malaria is a disease that claims about half a million lives annually, mainly children. There are 5 Plasmodium species that cause malaria; namely, P. falciparum, P. ovale, P. malariae, P. knowlesi and P. vivax. P. falciparum is the most virulent of them all. The parasite upregulates some heat shock proteins (Hsps) in response to stress it encounters during its life cycle. These Hsps play a major role in proteostasis. The drug resistance of P. falciparum to traditionally used remedies has led to a need for the development of novel drugs. Hsps have been implicated as antimalarial drug targets. Hsps act as molecular chaperones and some make complexes, which are important in facilitating protein folding. As an example, heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90) form a functional complex through an adaptor protein, Hsp70-Hsp90 organizing protein (Hop). P. falciparum expresses six Hsp70s that are localized in different subcellular compartments. Amongst them, P. falciparum Hsp70-x (PfHsp70-x), is exported to the erythrocyte where it is implicated in host cell remodeling. PfHsp70-x possesses an ATPase domain, substrate binding domain and a C-terminal subdomain. PfHsp70-x possesses an EEVN motif on its C-terminus which is implicated in interactions with co-chaperones amongst them, Hop. Although some of the chaperone functions of PfHsp70-x have been reported, its interaction with human chaperones has not been investigated. The availability of PfHsp70-x in the infected erythrocyte cytosol presents a possibility that this protein may functionally cooperate with human Hsp90 via human Hop (human Hop). This hypothesis that PfHsp70-x interacts with human chaperones is strengthened by the absence of Hsp90 and Hop of parasite origin in the infected erythrocytes. The main aim of this study was to explore the chaperone activity of PfHsp70-x and its functional co-operation with human Hop. Recombinant PfHsp70-x (full length and EEVN deletion mutant) proteins were expressed in E. coli XL1 Blue cells and purified using nickel affinity chromatography. PfHsp70-x was found to be structurally comprised of mostly alpha helices and demonstrated heat stability based on circular dichroism (CD) spectrometry studies. It was established that the EEVN motif may be important for the ATPase activity of PfHsp70-x. However, it was established that the EEVN motif was not important in regulating the holdase chaperone (protein aggregation suppression) function of PfHsp70-x. Furthermore, PfHsp70-x and its mutant preferentially bound to asparagine-rich peptides. Parasite proteins have high asparagine repeat regions as compared to human proteins. In addition, preference for asparagine-rich proteins iii could signify that PfHsp70-x is biased towards binding proteins of parasitic origin. Surface plasmon resonance (SPR) analysis suggested that PfHsp70-x interacts with human Hop with relatively higher affinity compared to its EEVN minus derivative. In conclusion, the removal of the EEVN motif of PfHsp70-x does not affect the chaperone function of PfHsp70-x. However, the EEVN motif is essential for the interaction of PfHsp70-x with human Hop.

MSc Applied Mathematics) / Department of Mathematics and Applied Mathematics / See the attached abstract below

MSc (Biochemistry) / Department of Biochemistry / Plasmodium falciparum is a unicellular protozoan parasite that causes malaria in humans. The parasite is passed to humans through mosquito bites and migrates to the liver before it infects host erythrocytes. It is at the erythrocytic stage of development that the parasite causes malaria pathology. Malaria is characterized by the modification of host erythrocytes making them cytoadherent. This is as a result of formation of protein complexes (knobs) on the surface of the erythrocyte. The knobs that develop on the surface of the erythrocyte are constituted by proteins of host origin as well as some proteins that the parasite ‘exports’ to the host cell surface. Nearly 550 parasite proteins are thought to be exported to the infected erythrocyte. Amongst the exported proteins is P. falciparum heat shock protein 70-x (PfHsp70-x). Hsp70 proteins are known to maintain protein homeostasis. Thus, the export of PfHsp70-x may be important for maintaining protein homeostasis in the host cell. PfHsp70-x is not essential for parasite survival although is implicated in the development of parasite virulence. This is possibly through its role in facilitating the trafficking of parasite proteins to the erythrocyte as well as supporting the formation of protein complexes that constitute the knobs that develop on the surface of the infected erythrocyte. The main objective of the current study was to investigate protein interaction partners of PfHsp70-x. It is generally believed that PfHsp70-x interacts with various proteins of human and parasite origin. Potential candidate interactors include its protein substrates, Hsp70 co-chaperones such as Hsp40 members, and human Hsp70-Hsp90 organizing protein (hHop). The establishment of the PfHsp70-x interactome would highlight the possible role of PfHsp70-x in the development of malaria pathogenicity. Based on bioinformatics analysis, PfHsp70-x was predicted to interact with some exported P. falciparum Hsp40s, hHop and human Hsp90 (hHsp90). Recombinant forms of PfHsp70-x (full length and a truncated form that lacks the C-terminal EEVN motif implicated in co-chaperone binding) were expressed in E. coli BL21 Star (DE3) cells. Recombinant hHop and hHsp70 were expressed in E. coli JM109 (DE3) cells. The proteins were successfully purified using nickel affinity chromatography. Co-affinity chromatography using recombinant PfHsp70-x and immuno-affinity chromatography using PfHsp70-x specific antibody did not confirm the direct interaction of PfHsp70-x with human Hop. However, the direct interaction of hHop and PfHsp70-x has previously been validated in vitro and the current bioinformatics data support ii the existence of such a complex. PfHsp70-x was not stable in the cell lysate that was prepared and this could explain why its interaction with hHop could not be ascertained. However, taken together the evidence from a previous independent study, and the predicted interaction of PfHsp70-x with human chaperones suggests cooperation of chaperone systems which possibly facilitates the folding and function of parasite proteins that are exported to the infected erythrocyte. / NRF

Safety, tolerability and efficacy of itraconazole and amphotericin B (AMB) were compared for empirical antifungal treatment of febrile neutropenic cancer patients. Patients and Methods: In an open, randomised study, 162 patients with at least 72 h of antimicrobial treatment received either intravenous followed by oral itraconazole suspension or intravenous AMB for a maximum of 28 days. Permanent discontinuation of study medication due to any adverse event was the primary safety parameter. Efficacy parameters included response and success rate for both treatment groups. Results: Significantly fewer itraconazole patients discontinued treatment due to any adverse event (22.2 vs. 56.8% AMB; p < 0.0001). The main reason for discontinuation was a rise in serum creatinine (1.2% itraconazole vs. 23.5% AMB). Renal toxicity was significantly higher and more drug-related adverse events occurred in the AMB group. Intention-to-treat (ITT) analysis showed favourable efficacy for itraconazole: response and success rate were both significantly higher than for AMB (61.7 vs. 42% and 70.4 vs. 49.3%, both p < 0.0001). Treatment failure was markedly reduced in itraconazole patients (25.9 vs. 43.2%), largely due to the better tolerability. Conclusions: Itraconazole was tolerated significantly better than conventional AMB and also showed advantages regarding efficacy. This study confirms the role of itraconazole as a useful and safe agent in empirical antifungal therapy of febrile neutropenic cancer patients. / Hintergrund: Es wurden die Sicherheit, Verträglichkeit und Wirksamkeit von Itraconazol und Amphotericin B (AMB) in der antimykotischen Therapie der persistierend febrilen Neutropenie verglichen. Patienten und Methoden: In einer offenen, randomisierten Studie erhielten 162 Patienten mit mindestens 72-stündiger antibiotischer Therapie entweder Itraconazol (erst intravenös, dann oral) oder AMB (intravenös) für maximal 28 Tage. Primärer Sicherheitsparameter war die dauerhafte Unterbrechung der Studienmedikation aufgrund von Nebenwirkungen. Die Wirksamkeitsparameter umfassten die Ansprech- und Erfolgsrate für beide Behandlungsgruppen. Ergebnisse: Signifikant weniger Itraconazol-Patienten brachen die Behandlung wegen Nebenwirkungen ab (22,2 vs. 56,8% AMB; p < 0,0001). Hauptursache für Studienabbrüche war der Anstieg des Serum-Kreatinin-Spiegels (1,2% Itraconazol vs. 23,5% AMB). Nephrotoxische und weitere Nebenwirkungen traten im AMB-Studienarm signifikant häufiger auf. Intention-to-Treat (ITT)-Analysen zeigten eine bessere Wirksamkeit von Itraconazol: Ansprech- und Erfolgsrate waren signifikant höher als unter AMB (61,7 vs. 42% und 70,4 vs. 49,3%, beide p < 0,0001). Behandlungsversagen trat bei Itraconazol-Patienten merklich weniger auf (25,9 vs. 43,2%). Schlussfolgerungen: Die Verträglichkeit von Itraconazol war signifikant höher als beim herkömmlichen AMB. Itraconazol zeigte ebenfalls Vorteile in der Wirksamkeit. Diese Studie bestätigt die Rolle von Itraconazol als sinnvolles und sicheres Medikament in der empirischen antimykotischen Therapie von fiebrigen neutropenischen Tumorpatienten. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

La France est le pays industrialisé le plus touché par le paludisme d’importation avec environ 4735 de cas importés et répertoriés en 2016. Les voyageurs migrants, originaires des pays où sévit le paludisme et résidant en France, représentent 82,2 % des cas d’infections palustres. Cette thèse cherche principalement à analyser la question du recours à la prévention du risque palustre auprès des voyageurs migrants originaires des pays d’Afrique Subsaharienne de Bordeaux. À partir d’observations directes et d’entretiens individuels avec différents acteurs, cette recherche montre une hétérogénéité des situations d’exposition au risque palustre lors du retour temporaire au pays d’origine. Ce risque dépend des situations expérientielles, et socio-économiques, ainsi que des charges qu’il est supposé y assumer. Lorsque ces charges sont importantes, le voyageur migrant a tendance à hiérarchiser les risques, avec une non-priorisation du palustre au profit du risque de « toubabisation », socialement moins accepté. La non-priorisation du risque de paludisme est accentuée par une perception banalisante, ordinaire et quotidienne du paludisme en contexte de migration et par le non-remboursement de la chimioprophylaxie par la Caisse Nationale Assurance Maladie. Ce travail montre que le non recours à la chimioprophylaxie est influencé par l’absence d’expérience du paludisme en France et de paludisme grave dans le pays d’origine. Souvent, il faut que l’expérience de cette maladie soit vécue et perçue dans le pays d’accueil pour qu’elle induise un changement de perception et donc, un recours futur à la prévention. Sur le plan thérapeutique, cette thèse met en évidence des retards de diagnostic du paludisme en médecine générale. Ces retards sont causés par l’absence d’association de la « fièvre du retour » et des symptômes associés à un accès palustre, et par son « exotisme » en France. À ce titre, cette recherche apporte une contribution aux réflexions dans les champs de l’anthropologie de la santé et de l’anthropologie du risque lié au voyage avec comme exemple les voyageurs migrants exposés au risque palustre. / France is the industrialized country most assigned by import malaria with around 4735 imported and registered cases in 2016. Migrant travelers from malaria-affected countries residing in France account for 82.2% of all malaria cases. malaria infections. This thesis mainly seeks to analyze the issue of the use of malaria risk prevention among migrant travelers from sub-Saharan African countries in Bordeaux. Based on direct observations and individual interviews with different actors, this research shows the heterogeneity of situations of exposure to malaria risk during temporary return to the country of origin. This risk depends on the experiential and socio-economic situations, as well as the burdens it is supposed to assume. When these burdens are significant, the migrant traveler tends to prioritize the risks, with a non-prioritization of malaria control in favor of the risk of “toubabisation”, socially less accepted. The non-prioritization of the risk of malaria is accentuated by a banal, ordinary and daily perception of malaria in the context of migration and by the non-reimbursement of chemoprophylaxis by the National Health Insurance Fund. This work shows that the non-use of chemoprophylaxis is influenced by the lack of experience of malaria in France and severe malaria in the country of origin. Often, the experience of this disease must be experienced and perceived in the host country to induce a change of perception and therefore a future use of prevention. Therapeutically, this thesis highlights delayed diagnosis of malaria in general practice. These delays are caused by the lack of association of the “return fever” and symptoms associated with malaria, and by its “exoticism” in France. As such, this research contributes to reflections in the fields of anthropology of health and anthropology of travel risk, with the example of migrant travelers exposed to malaria risk.

Geographically, Pakistan is in the western part of south Asia at about 24-37 °N latitudes and62-75 °E longitudes. Livestock and agriculture are two major sectors in Pakistan and play animportant role in the country economy.The tick infestation in livestock is not only devastating for animals and their products but alsobecome the cause of transmission of pathogens into humans. Crimean Congo fever (CCHF) isa viral tick-borne fatal disease. The dissemination of ticks and amplification of Crimean Congofever (CCHF) pathogen throughout the tick-animals-tick cycle, increases risk of transmissionto humans many times. In Pakistan, cases are reported in all areas, particularly those areaswhich lie on the border to CCHF endemic countries. There is a high prevalence of CCHF inboth Baluchistan and Khyber Pakhtunkhwa regions. Baluchistan is bordering with Afghanistanand Iran and Khyber Pakhtunkhwa with Afghanistan. Linear regression analysis revealed apositive significant association of high level of CCHF cases in livestock, with camels, goatsand sheep. The literacy rate is negatively significantly corelated with the numbers of cases.Statistical analysis of border effect revealed a high positive significant correlation of CCHFprevalence in areas near to borders. Both Baluchistan and Khyber Pakhtunkhwa (KPK) haslow literacy rate than other regions of Pakistan. Islamabad (capital city) has a higher literacyrate than all other regions but there is still a high CCHF prevalence. This is not only becauseof high population density but people from other regions, particularly from Baluchistan andKPK come here for animals selling or to seeking medical facilities in the large city hospitals.The study gives a proof that illiteracy and borders are the major respondent factors in theCCHF incidences and prevalence in an area. There is a need to raise awareness about ticksand tick-borne disease in the public and establishment of monitoring system across the bordersto prevent the spread of CCHF virus.

Die Dissertation befasst sich mit der Fragestellung der Tenazität sowie Desinfektion des Virus der Afrikanischen Schweinepest in verschiedenen Waldböden bei Kontamination durch infiziertes verendetes Schwarzwild. / The dissertation deals with the question of tenacity as well as disinfection of African swine fever virus in different types of forest soil in case of contamination by infected dead wild boar.

Zusammenfassung Katja Schwartau Peripartale hämatologische und klinisch-chemische Blutuntersuchungen zur Frühdiagnostik der Dislocatio abomasi, Gebärparese, Retentio secundinarum und Mastitis bei Milchkühen Medizinische Tierklinik der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im Mai 2011 Bibliographische Angaben 94 Seiten, 22 Abbildungen, 19 Tabellen, 210 Literaturangaben, Schlüsselwörter: Labmagenverlagerung, Gebärparese, Retentio secundinarum, Mastitis, Kuh Produktionskrankheiten haben in den letzten Jahren immer mehr an Bedeutung gewonnen. Diese leistungsassoziierten Bestandserkrankungen tragen wesentlich zur kurzen Nutzungsdauer von ca. 2,5 Jahren der Milchkühe bei. Es ist deshalb besonders wichtig, ihre Prophylaxe einschließlich der Früherkennung in den Vordergrund zu stellen. In der vorliegenden Untersuchung wurden deshalb frühdiagnostische Möglichkeiten der LMV (Labmagenverlagerung), GP (Gebärparese), Retentio sec. (Retentio secundinarum) und Mastitis geprüft. Des Weiteren wurden die Kühe in einer Gruppe „krank“ und einer Gruppe „gesund“ gegenübergestellt, um durch Stoffwechselabweichungen generell subklinische Veränderungen zu erkennen, die Hinweise auf bevorstehende Erkrankungen geben. Besondere Beachtung fand für die Bewertung des Erkrankungsrisikos die odds ratio. In die Untersuchung wurden insgesamt 398 Schwarzbunte Kühe einbezogen. 49 Tiere waren an einer LMV, 121 Tiere an einer GP, 131 an einer Retentio sec. und 119 Tiere an einer Mastitis erkrankt. Im Gruppenvergleich gesund/krank wurden 347 erkrankte Kühe mit 51 klinisch gesunden Tieren verglichen. Es wurden bei allen Kühen 14-7 d a.p. (Tage ante partum) und 3 d p.p. (Tage post partum) Blutproben entnommen. Es wurden Parameter des Energie-, Fett- und Leberstoffwechsels (FFS [Freie Fettsäuren], BHB [ß-0H-Butyrat], Cholesterol, Glucose, Insulin, AST [Aspartat-Amino-Transferase], Bilirubin), des Eiweißstoffwechsels (Albumin, Haptoglobin, TP [Gesamt-Eiweiß], Harnstoff, Kreatinin) und der Leukozyten sowie des Mineralstoffwechsels (Na [Natrium], K [Kalium], Cl [Chlorid], Ca [Calcium], Pi [anorganisches Phosphat], AP [Alkalische Phosphatase]) und der CK [Creatinkinase] bestimmt und mit gesunden Kühen verglichen. 92 Auf das Risiko einer LMV weisen a.p. besonders Konzentrationssteigerungen des Haptoglobins hin. Aber auch die Mediane der Glucose und der AP liegen außerhalb des Referenzbereichs bei Tieren, die später an einer LMV erkranken. Drei d p.p. kommen signifikante Konzentrationsanstiege der FFS, des BHB und des Bilirubin sowie signifikante Konzentrationsabnahmen des Insulin (odds ratio 8,43) bis unter den Normbereich hinzu. Die Aktivitäten der AP und auch die Konzentrationen von Cholesterol und Ca bleiben ebenfalls unter dem Normbereich. Die Mediane der AST-Aktivität und der Haptoglobinkonzentration liegen oberhalb des Referenzbereichs. Auf das Risiko einer GP weisen a.p. und p.p die verminderte AP-Aktivität sowie Konzentrationsanstiege der FFS (odds ratio 1,78) hin. Drei d p.p ergänzen die Konzentrationen des BHB, des Bilirubins und des Haptoglobins (odds ratio 4,59) oberhalb der Referenzbereiche die Veränderungen. Der Median der Insulinkonzentration liegt 3 d p.p. unter dem Referenzbereich. Einer Retentio sec. gehen erhöhte Glucosekonzentrationen a.p. voraus. Der Median der AP-Aktivitäten liegt schon a.p. unter dem Normbereich. Drei d p.p. unterscheidet er sich signifikant von Kühen ohne Retentio sec. Hinweise auf Mastitiden liefern p.p. die Konzentrationen des BHB (odds ratio 1,78). Die Mediane der Glucosekonzentrationen liegen a.p. oberhalb und die der AP-Aktivitäten unterhalb der Referenzbereiche. Drei d p.p. kommen Steigerungen der Haptoglobin-, Glucose- und Bilirubinkonzentrationen sowie Aktivitätssteigerungen der AST bis über den Normbereich hinzu. Als Besonderheit liegen die Ca- und Pi-Konzentrationen aufgrund des geringeren Abflusses bei einer verminderten Milchleistung signifikant über denen der gesunden Kühe. Für die Entstehung postpartaler Erkrankungen generell verdienen die signifikanten Konzentrationssteigerungen der Glucose sowie die Abnahme der AP-Aktivität besondere Beachtung. Das BHB (odds ratio 1,92 a.p.) und die CK (odds ratio 2,17 a.p.) weisen auf ein erhöhtes Krankheitsrisiko hin. Drei d p.p. kommen zu den Veränderungen dieser Parameter noch signifikante Konzentrations- bzw. Aktivitätssteigerungen der FFS, des BHB, der CK, des Bilirubins, der AST und des Haptoglobins (odds ratio 4,61) sowie erniedrigte Ca-Konzentrationen hinzu. Die Untersuchungen haben gezeigt, dass a.p. generell Abweichungen des Energiestoffwechsels und im Besonderen gesteigerte Glucosekonzentrationen sowie erniedrigte AP-Aktivitäten ein erhöhtes Risiko für postpartale Erkrankungen anzeigen. Höhere Aussagekraft besitzen Kontrollen am 3. d p.p. mit den Parametern Insulin (odds ratio 8,4), FFS, BHB und Haptoglobin (odds ratio 4,61), deren Konzentrationen gegenüber gesunden Kühen signifikant abweichen. Ähnlich gute Eignung zeigen, Bilirubin, AST und Ca.

Introducción: La fiebre de Oropouche es una enfermedad infecciosa causada por el virus Oropouche (OROV). El diagnóstico y predicción del cuadro clínico continúa siendo un gran desafío para los médicos quienes manejan a los pacientes con síndrome febril agudo. Se han asociado diversos síntomas con la infección por virus OROV en pacientes con síndrome febril; sin embargo, a la fecha no existe una regla de predicción clínica. Objetivo: Evaluar el rendimiento de un modelo de predicción basado únicamente en signos y síntomas para diagnosticar la infección por el virus de Oropouche en pacientes con síndrome febril agudo. Materiales y Métodos: Estudio de validación, que incluyó a 923 pacientes con síndrome febril agudo registrados en la base de datos de la Vigilancia Epidemiológica de tres zonas del Perú durante los años 2015-2016. Resultados: Un total de 97 (19.0%) pacientes fueron positivos para infección por Oropouche en el grupo de desarrollo y 54 (23.6%) para el grupo de validación. El área bajo la curva fue de 0.65 y la sensibilidad, especificidad, VPP, VPN, LR+ y LR- fueron de 78.2%, 35.1%, 27.6%, 83.6%, 1.20 y 0.62 respectivamente. Conclusión: El desarrollo de un modelo de predicción clínica para el diagnóstico de OROV basado únicamente en signos y síntomas no funcionó bien debido a que la clínica es inespecífica y se relaciona con otras infecciones arbovirales, lo cual dificulta la predicción del diagnóstico, especialmente en áreas endémicas de coinfección de estas enfermedades. Se recomienda la vigilancia epidemiológica de OROV utilizando pruebas como PCR molecular. / Background. Oropouche fever is an infectious disease caused by the Oropouche virus (OROV). The diagnosis and prediction of the clinical picture continue to be a great challenge for clinicians who manage patients with acute febrile syndrome. Several symptoms have been associated with OROV virus infection in patients with febrile syndrome; however, to date, there is no clinical prediction rule. Objective. To assess the performance of a prediction model based solely on signs and symptoms to diagnose Oropouche virus infection in patients with acute febrile syndrome. Materials and Methods. Validation study, which included 923 patients with acute febrile syndrome registered in the Epidemiological Surveillance database of three areas of Peru during the years 2015-2016. Results. A total of 97 patients (19%) were positive for OROV infection in the development group and 23.6% in the validation group. The area under the curve was 0.65 and the sensitivity, specificity, PPV, NPV, LR + and LR- were 78.2%, 35.1%, 27.6%, 83.6%, 1.20 and 0.62, respectively. Conclusions. The development of a clinical prediction model for the diagnosis of Oropouche based solely on signs and symptoms does not work well because the clinic is nonspecific and is related to other arbovirus infections, which makes it difficult to predict the diagnosis, especially in areas co-infection endemics of these diseases. Epidemiological surveillance of OROV using laboratory tests such as molecular PCR is recommended. / Tesis

Japanese encephalitis virus (JEV) and West Nile virus (WNV) are closely related Flaviviruses that are important arthropod-borne human pathogens. Both of these viruses can cause encephalitis with significant morbidity and mortality after infection. Flaviviruses co-circulate in many areas of the world, which raises the risk for sequential infection between heterologous viruses. Sequential infection between dengue virus serotypes can lead to cross-protection, but in some cases, it leads to a severe outcome, dengue hemorrhagic fever. Previous work in hamsters and non-human primates demonstrated that prior JEV immunity protects against a lethal WNV infection. However, the ability of prior WNV immunity to protect against a lethal JEV infection has been inconclusive. WNV-immune hamsters were fully protected from JEV viremia, but in non-human primates, prior WNV-immunity only reduced disease severity, with symptoms of encephalitis still observed. These differences in cross-protection led to further investigation on the directionality as well as the underlying mechanisms for this phenomenon. Previous work in our lab found that JEV-immune C57BL/6J (B6) mice were fully protected against a lethal WNV infection, and JEV-immune CD4+ and CD8+ T cells were required for this cross-protection. In other mouse models, memory cross-reactive CD4+ and CD8+ T cell responses may induce protection or immunopathology upon secondary heterologous viral challenge. We hypothesize that JEV/WNV cross-reactive CD4+and CD8+ T cells preferentially expand upon 2o infection and contribute to cross-protection. To elucidate the potential role of T cells in sequential flavivirus infection, we identified and characterized cross-reactive CD4+ and CD8+ T cell responses between JEV and WNV. A previously reported WNV NS4b CD8+ T cell epitope and its JEV variant elicited CD8+ T cell responses in both JEV- and WNV-infected mice. Despite similarities in viral burden for pathogenic JEV and WNV viruses, CD8+ T cells from pathogenic JEV-infected mice exhibited functional and phenotypic profiles similar to those seen for the attenuated JEV strain. We believe the differences in the CD8+ T cell responses during primary JEV and WNV infection are due at least in part to the low levels of peripheral replication seen in JEV-infected mice compared to WNV-infected mice. We also found that WNV-immune B6 mice were protected against a lethal JEV infection. Cross-reactive CD8+ T cells in JEV-immune mice rapidly expanded after WNV infection. Even though WNV-immune mice had higher frequencies of memory CD8+ T cells, cross-reactive CD8+ T cells did not expand after secondary JEV infection. Neutralizing antibodies to JEV were detected in WNV-immune mice; however, cross-reactive CD8+ T cells did not expand even in the absence of these cross-reactive neutralizing antibodies. We did not detect any differences in the CD8+ T cell repertoires between JEV- and WNV-infected mice nor were WNV-immune CD8+ T cells functionally exhausted. In fact, proliferation of memory CD8+ T cells did not correlate with the ability of WNV-immune CD8+ T cells to restrict recombinant vaccinia viruses expressing the cross-reactive epitope or lyse peptide-coated targets. These data suggest that the higher frequency of memory CD8+ T cells and cross-reactive antibodies in WNV-immune mice are better able to prevent neuroinvasion following 2o JEV infection.