Mother-to-child transmission (MTCT) of HIV accounts for more than 90% of pediatric infections worldwide, yet the mechanism of vertical transfer remains unknown. The feline immunodeficiency virus (FIV)-infected cat is a cost-effective, small-animal model of HIV pathogenesis and MTCT, which produces a high rate of reproductive failure and fetal infection in litters delivered at early- and late-term gestation. Our previous data suggest that FIV infection may dysregulate placental cytokines and compromise pregnancy. We hypothesized that FIV-infection may cause dysregulation of placental cytokine expression, and aberrant expression of these cytokines may potentiate inflammation and transplacental infections. The purpose of this project was to evaluate feline placental immunopathology at the whole and cellular levels during early- and late-term gestation to understand how lentiviruses may perturb placental immune parameters. To determine whether placentas were vulnerable to FIV infection, we quantified the expression of the FIV receptors, CD134 and CXCR4, in RNA extracted from late-term placental tissue. We found higher expression of CD134 and CXCR4 in placentas from successful pregnancies. To evaluate relative cytokine expression in randomly-sampled, whole placental specimens, we quantified representative pro- and anti-inflammatory cytokines and a chemokine. IL-6 and IL-12p35 were increased in early-gestation, FIV-infected queens; IL-6 was increased in late-gestation, FIV-infected queens. To evaluate placental immunopathology at the cellular level, we developed a novel immunohistochemistry method to identify trophoblastic cells selectively. Trophoblasts were collected using laser capture microdissection, and RNA was extracted from captured cells. We detected expression of several anti- and pro-inflammatory cytokines and the chemokine receptor CXCR4 (the FIV co-receptor) in trophoblasts at both stages of gestation. However, we failed to detect expression of other cytokines and CD134, the FIV primary receptor. FIV infection slightly lowered expression of all cytokines at both early and late pregnancy, although only the decrease in IL-5, from early pregnancy, and IL-4 and IL-12p35, from late pregnancy, reached significant levels. Fetal non-viability was associated with decreased trophoblast expression of IL-4, IL-6, IL-12p35, and CXCR4 at early gestation and decreased expression of IL-4, IL-12p35, IL-12p40 at late gestation. Collectively, these data indicate that FIV infection negatively impacts pregnancy outcome and alters placental immunomodulation.

We are using the feline immunodeficiency virus (FIV)-infected cat to model HIV mother-to-child-transmission (MTCT). Vertical transmission of either virus may result not only in infected offspring, but also failed pregnancy.In HIV infections, maternal hematological and virological parameters predict MTCT.We hypothesized that such parameters would likewise be predictors of FIV vertical transfer. We inoculated ten cats with FIV-B-2542; 10 cats were uninoculated. Cats were allowed to breed naturally. Fetuses were delivered at approximately week 3 (early) gestation by cesarean section. Fetal and placental tissues were collected.Blood samples were collected from the day of inoculation through delivery. We quantified CD4:CD8 T cell ratios, proviral load, and plasma viremia, and monitored seroreactivity to FIV proteins in longitudinal sera from both groups of cats. We documented clinical and reproductive outcome. The infected group produced reduced litter size and more failed pregnancies; CD4:CD8 ratios were depressed by 3.5 months p.i.Proviral DNA was detected in 14 of 14 (100%) placentas tested and 12 of 14 (86%) fetuses. However, the parameters assessed were not predictive of reproductive outcome and suggested a role for placental immunopathology in compromised pregnancy.Regulatory T cells (Treg) are anti-inflammatory and essential in maintaining pregnancy.Th17 cells are pro-inflammatory and associated with pregnancy failure. The activation of these cell populations is regulated by the cytokines TGF-? and IL-6. We hypothesized that placental immunology may result from altered dynamics of these cell populations.Using immunofluorescence confocal microscopy to measure Treg and Th17 markers FoxP3 and ROR ? , respectively, we quantified these cells in placental specimens from FIV-infected and control cats at early and late (week 8) gestation.Significantly higher levels of ROR ? were measured in FIV-infected placentas at early pregnancy; these cells co-localized at the maternaletal interface. We quantified the expression of Treg immunomodulators by quantitative PCR, noting higher expression of TGF-? in infected queens.A positive correlation of ROR ? with IL-6 occurred in control placentas, as predicted, but not in infected placentas.Collectively, the data suggest that an inflammatory placental microenvironment at early pregnancy in infected queens may result, in part, from dysregulation of the Treg/Th17 balance.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiv, 144 p.; also includes graphics (some col.). Includes abstract and vita. Co-advisors: Lawrence E. Mathes and Maria H. Neff, Dept. of Veterinary Biosciences. Includes bibliographical references (p. 122-144).

In the present studies, the essential role of inducer cells for the induction of soluble anti-viral activity against feline immunodeficiency virus (FIV) was investigated. Induction of suppression of FIV replication was found to not strictly require autologous cells and was probably not FIV specific. Suppression was maximum when the inducer cells and the effector CD8+ T cells were in contact with each other, suggesting a potential role for membrane antigen interactions and/or cytokines in the induction process. Additionally, flow cytometry analysis demonstrated a significant increase in the percentage of CD8+ B7-1+ T cells in the peripheral blood of chronically FIV infected cats as compared with uninfected cats. Examination of the FIV V3-V4 envelope sequences from PBMC, lymph nodes and spleen from six cats chronically infected from three to six years with the molecular clone of FIV-PPR did not demonstrate viral variants specific for the tissues examined, emphasizing the critical role of the initial diversity and virulence of the infecting virus inoculum. Additionally, in vitro CD8+ T cell antiviral activity demonstrated by four of the six cats could have led to the control of virus replication in vivo, resulting in the uniform viral variants observed. Infection of specific pathogen free cats with FIV-TX53, an FIV isolate that belongs to an emerging subtype more closely related to FIV clade B, demonstrated an acute stage infection characterized by lymphoadenopathy and a viral dose dependent decline of CD4+/CD8+ T cell ratios below 1 by 11 weeks post infection. Interestingly, an expansion of CD8 low population of CD8+ T cells was observed in the infected cats. The soluble antiviral activity generated from inducer T cell stimulated CD8+ T cells from FIV-A-PPR infected cats also suppressed in vitro replication of the emerging FIV-TX53 and FIV-TX078 isolates. This is the first report demonstrating that the CD8+ T cell antiviral activity is inter-clade effective among FIV strains. As the success of a FIV vaccine could be hampered by occurrence of highly divergent viral variants in the fields, the exploitation of this innate, soluble anti-FIV activity could contribute to the design of novel, safe and complementary anti-FIV therapeutic strategies.

In the present studies, the essential role of inducer cells for the induction of soluble anti-viral activity against feline immunodeficiency virus (FIV) was investigated. Induction of suppression of FIV replication was found to not strictly require autologous cells and was probably not FIV specific. Suppression was maximum when the inducer cells and the effector CD8+ T cells were in contact with each other, suggesting a potential role for membrane antigen interactions and/or cytokines in the induction process. Additionally, flow cytometry analysis demonstrated a significant increase in the percentage of CD8+ B7-1+ T cells in the peripheral blood of chronically FIV infected cats as compared with uninfected cats. Examination of the FIV V3-V4 envelope sequences from PBMC, lymph nodes and spleen from six cats chronically infected from three to six years with the molecular clone of FIV-PPR did not demonstrate viral variants specific for the tissues examined, emphasizing the critical role of the initial diversity and virulence of the infecting virus inoculum. Additionally, in vitro CD8+ T cell antiviral activity demonstrated by four of the six cats could have led to the control of virus replication in vivo, resulting in the uniform viral variants observed. Infection of specific pathogen free cats with FIV-TX53, an FIV isolate that belongs to an emerging subtype more closely related to FIV clade B, demonstrated an acute stage infection characterized by lymphoadenopathy and a viral dose dependent decline of CD4+/CD8+ T cell ratios below 1 by 11 weeks post infection. Interestingly, an expansion of CD8 low population of CD8+ T cells was observed in the infected cats. The soluble antiviral activity generated from inducer T cell stimulated CD8+ T cells from FIV-A-PPR infected cats also suppressed in vitro replication of the emerging FIV-TX53 and FIV-TX078 isolates. This is the first report demonstrating that the CD8+ T cell antiviral activity is inter-clade effective among FIV strains. As the success of a FIV vaccine could be hampered by occurrence of highly divergent viral variants in the fields, the exploitation of this innate, soluble anti-FIV activity could contribute to the design of novel, safe and complementary anti-FIV therapeutic strategies.

Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 60-90).

Orientador: João Pessoa Araújo Júnior / Banca: Lenice do Rosário de Souza / Banca: Alexandre Secorum Borges / Resumo: O Vírus da Imunodeficiência Felina (FIV) é um lentivírus que causa uma síndrome de imunodeficiência em gatos domésticos. O FIV tem sido particularmente utilizado em estudos de resistência viral aos análogos de nucleosídeos devido a Transcriptase Reversa (TR) apresentar propriedades físicas, catalíticas e sensibilidade às drogas semelhantes à TR do HIV. Os objetivos desse trabalho foram tratar com AZT gatos naturalmente infectados com o FIV, fazer o monitoramento da carga viral e DNA proviral por PCR em tempo real e monitoramento genético por seqüenciamento. Dos 12 animais infectados, 6 receberam o AZT na dose de 10mg/kg/dia e 6 receberam placebo. Durante 96 dias de tratamento, o plasma e sangue destes animais foram analisado com relação à carga viral e concentração relativa de DNA proviral utilizando-se a técnica de quantificação relativa por PCR em tempo real com SYBR Green, desenvolvida por nossa equipe. Além disso, foi realizado o sequenciamento genético da região que codifica a TR de 3 dos animais. Foi realizada com sucesso a padronização da PCR em tempo real para quantificação relativa do FIV. Não houve diferença estatisticamente significativa da carga viral ou do DNA proviral entre os grupos tratado e controle. O seqüenciamento genético revelou a presença de lisina na posição 41 do sítio ativo da TR. A presença deste aminoácido confere até 4 vezes menor sensibilidade ao AZT em mutantes do HIV. Por possuir alta estabilidade genética, supomos que os vírus dos demais animais não sequenciados possuem também a 41-lisina A presença da 41-lisina pode ser uma das possíveis explicações para a falha do tratamento com AZT. Outra hipótese é a de que a dose fornecida não foi adequada. / Abstract: Feline Immunodeficiency Virus (FIV) is a lentivirus which causes a progressive disruption of the host's immune functions. FIV has been particularly used as a model for studies in retroviral resistance to nucleoside analogs because its similarities in physical properties, catalytic and sensitivity in comparison with HIV/RT. The aims of this work were to treat cats naturally infected with FIV, quantify viral load and proviral DNA by real time quantitative PCR with SYBR Green and analyze the viral nucleotide sequence. From 12 animals naturally infected, 6 received AZT at a dose of 10mg/kg/day and 6 received placebo. During 96 days of treatment, viral load and concentration of proviral DNA were measured by relative quantitative real time PCR developed by our staff. The nucleotide sequence of the RT encoding region was also achieved for 3 animals. The real time PCR relative quantification was successfully standardized for FIV. There was no significant statistical difference between treated and control groups. The nucleotide sequence revealed a lysine at position 41 on the enzyme active site. This lysine confers 4-fold decreased sensitivity to AZT in HIV RT-mutants. FIV subtype B has high genetic stability and we purposed that the other virus not sequenced have the same amino acid and hypothesized that this mutations can be one of the reasons determining the failure of the treatment. The other hypothesis is that the dose was not adequate. / Mestre

The role that amniotic fluid (AF) may play in HIV vertical infection is unresolved. We used the FIV-infected cat model to study this question. We hypothesized that AF may be a source of fetal infection if the virus is present in the fluids. However, virus neutralizing (VN) antibodies in AF may limit vertical transfer. Fetuses were delivered from FIV-infected queens by cesarean section at early and late gestation. AFs were aspirated from intact fetal membranes and tested for viral antigen and RNA and for FIV-specific antibody. Randomlyselected samples were tested for VN activity using a syncytium reduction assay. Neither FIV antigen nor RNA was detected in any AFs. AFs and parallel serum samples from early and late pregnancy were positive for FIV-specific antibody. VN activity was detected in three early-term AFs and a parallel serum, but not late-term AFs. AF appears to play no appreciable role in FIV vertical transmission.

A gengivite crônica e intratável observada em gatos infectados pelo vírus da imunodeficiência felina (FIV) é um problema bastante freqüente na clínica de pequenos animais. O papel do FIV na etiologia da estomatite persistente ainda está por ser determinado. As manifestações orais são freqüentemente os primeiros sintomas observados em pacientes humanos infectados pelo HIV e podem ser usadas como indicadores da progressão da doença. O objetivo do presente estudo foi quantificar os linfócitos T CD4+, T CD8+ e a razão CD4+/CD8+ em uma colônia de gatos com gengivite crônica e naturalmente infectados pelo FIV. Para tanto, foram utilizados 20 gatos, todos apresentando gengivite com graus variando de 1 a 4. Desse total, 10 gatos não eram infectados pelo FIV e os outros 10 felinos eram infectados pelo FIV. Utilizou-se como controle 20 gatos sem gengivite, sendo 10 infectados pelo FIV e outros 10 não infectados pelo Retrovírus. As contagens dos linfócitos T CD4+ e CD8+ foram realizadas utilizando-se a técnica de citometria de fluxo. Os resultados obtidos demonstraram que os gatos com gengivite e infectados pelo FIV apresentaram uma contagem significativamente menor de linfócitos T CD4+ quando comparado aos gatos com gengivite e não infectados pelo FIV. Não houve diferença significativa na contagem de linfócitos T CD8+ entre os gatos com gengivite, infectados ou não pelo FIV. A razão CD4+/CD8+ também se mostrou em declínio nos gatos com gengivite e infectados pelo FIV. Concluiu-se que nas condições do presente estudo, a infecção pelo FIV compromete a resposta imunológica de felino diante da inflamação gengival. / Chronic and intractable gingivitis in FIV-infected cats is a relatively common clinical problem in veterinary practice. The role of FIV in the etiology of persistent stomatitis is still undetermined. Oral manifestations often found in HIV-infected people are frequently the first clinical sign of the infection and can be considered as an indicator of the progression of the HIV infection. The purpose of this study was to evaluate the CD4+ and CD8+ T-lymphocytes count and CD4+:CD8+ ratio in a colony of cats with chronic gingivitis. To achieve these goals, a colony of twenty domestic shorthair cats was used. All cats had some degree of gingival inflammation with scores ranging from 1 through 4. Ten cats were FIV-positive and ten were FIV-negative. As a control, twenty cats without gingivitis were used (ten cats were FIV-positive and ten were FIV-negative). CD4+ and CD8+ T-lymphocytes counts were performed by means of flow cytometry in all forty cats and results compared. The results showed that cats with gingivitis and FIV-infected had a lower CD4+ T cells count than cats with gingivitis but not FIV-infected. There was no difference in CD8+ T lymphocytes count among the cats with gingivitis infected or not with the FIV. The CD4+:CD8+ ratio was lower in cats with gingivitis and FIV-infected. One can conclude that FIV infection induces immunological disorders in cats with gingival inflammation.

Gatos infectados naturalmente pelo vírus da imunodeficiência felina (FIV) desenvolvem uma síndrome semelhante à causada pela infecção pelo vírus da imunodeficiência humana (HIV), sendo a espécie felina um modelo promissor de estudo da infecção pelo HIV. Em humanos a nefropatia associada à infecção pelo HIV é uma causa comum e preocupante de complicação por resultar em insuficiência renal progressiva nos pacientes acometidos. Achados clínico-patológicos identificados em gatos naturalmente infectados pelo FIV também sugerem um envolvimento renal. Com o intuito de determinar a ocorrência de doença renal crônica (DRC) em gatos infectados pelo FIV e uma possível associação entre essas doenças, foi estudada uma população de 44 gatos, sendo 20 animais naturalmente infectados e 24 animais não-infectados, submetidos às mesmas condições higiênico-sanitárias, de dieta e quanto à exposição a agentes infecciosos. Os animais foram acompanhados durante um período de 18 meses, durante o qual foram realizadas dosagens periódicas de creatinina sérica e mensuração da relação proteína:creatinina urinária (RPC-U). A ocorrência de DRC em gatos infectados pelo FIV foi de 45%, maior em comparação aos 25% referentes ao grupo não-infectado, embora não tenha havido diferença estatisticamente significativa entre esses grupos. A proteinúria em pelo menos um momento foi observada em 60% dos gatos infectados pelo FIV e em 26,1% dos gatos não infectados (p= 0,037). Considerando proteinúria persistente como aquela observada em pelo menos 3 momentos consecutivos, os gatos infectados tiveram ocorrência de 30,8% em comparação a 6,7% referente ao grupo não infectado (p> 0,05). Houve associação entre o óbito e a DRC apenas nos gatos infectados (p= 0,02). Concluiu-se que, apesar de a ocorrência de doença renal crônica e de proteinúria não ter sido estatisticamente maior diante da infecção pelo FIV, a associação entre o óbito e a DRC nos animais infectados sugere que o FIV pode contribuir para o agravamento da DRC, levando a rápida deterioração do organismo e considerável diminuição da sobrevida. / Cats naturally infected with the feline immunodeficiency virus (FIV) develop a syndrome that share common characteristics with the human immunodeficiency virus (HIV) infection. For this reason, felines are considered a promising model for the study of HIV infection. HIV associated nephropathy is a common and concerning complication in human beings, resulting in progressive renal insufficiency. Likewise clinico-pathological findings in naturally infected cats suggest a renal involvement. To evaluate the occurrence of chronic kidney disease (CKD) in cats infected with FIV and to verify a possible association between both diseases, a population of 44 cats submitted to the same sanitary handling, diet and exposure to infectious agents was studied. Of these cats, 20 were naturally infected with FIV and 24 were free of FIV infection. Animals were periodically accompanied for a 18-month period through serum creatinine and urinary protein:creatinine ratio measures. The occurrence of CKD in cats infected with FIV was 45%, a value higher than the observed in non-infected cats (25%), but no statistical difference was found. Proteinuria in at least one moment of evaluation was observed in 60% of infected cats and in 26,1% of non-infected cats (p=0,037). Considering the criterion of persistent proteinuria as the observation of urinary protein excretion in at least 3 consecutive moments, infected cats exhibited occurrence of 30,8% compared with 6,7% in the non-infected group (p>0,05). It was observed an association between death and CKD only in the cats infected with FIV (p=0,02). In conclusion, despite occurrence of CKD and proteinuria have not been statistically higher in infected cats than in non-infected one, the association between death and CKD in FIV-infected cats suggests FIV may contribute for the worsening of CKD, resulting in a quicker organic dysfunction and marked reduction of survival.