Abstract Epidemiological and experimental studies indicate a causative role of viruses in malignancies. Recently, a link between bacterial infections and the development of cancer has been suggested. The purpose of this study was to evaluate the association between chlamydial infection and cancer. The association between C. trachomatis infection and cervix cancer was analysed in a prospective study. The presence of IgG antibodies to C. trachomatis and C. pneumoniae was determined from the serum samples of 182 Nordic women with invasive cervical carcinoma and 538 matched cancer-free controls by the microimmunofluorescence (MIF) method. Serum antibodies to C. trachomatis were associated with an increased risk for cervical squamous cell carcinoma (SCC) (OR 2.2, 95% CI 1.3-3.5), but not for cervical adenocarcinoma (OR 0.4, 95% CI 0.1-1.7). C. trachomatis serotype G was highly significantly associated with an increased risk for SCC (adjusted OR 6.6, 95% CI 1.6-27). The presence of serum IgG antibodies to more than one serotype of C. trachomatis, on the other hand, also increased the risk of SCC. The association between C. pneumoniae infection and lung cancer was analysed separately in men and women. C. pneumoniae-specific antibodies and immune complexes (IC) were analysed from 230 Finnish smoking males with lung cancer and their matched controls using serum samples collected before the lung cancer diagnosis. Suggestive chronic C. pneumoniae infection was associated with an increased risk for lung cancer (OR 1.6; 95% CI 1.0-2.3). The risk was increased especially in men younger than 60 years (OR 2.9; 95% CI 1.5-5.4), but not in the older age group (OR 0.9; 95% CI 0.5-1.6). Chlamydial antibodies and chlamydia-specific ICs were analysed from serum samples of 29 Finnish women with lung cancer and 87 matched cancer-free controls by MIF. The mean follow-up from serum sampling to cancer diagnosis was 6.7 years. IgG class antibodies to C. pneumoniae were common in pregnant Finnish women (66% among cases, 62% among controls), whereas IC-bound C. pneumoniae IgG antibodies were rare. No additional risk for lung cancer in association with chlamydial antibodies was found among women. The association between chlamydial infections and lymphomas was evaluated in a cross-sectional study. Seventy-two lymphoma patients from Tampere University Hospital and 72 matched controls were selected, and IgG antibodies and ICs to C. pneumoniae and C. trachomatis were analysed from their serum samples by MIF and enzyme immunoassay (EIA). The serological markers suggesting chronic chlamydial infection were associated with an increased risk for malignant lymphoma. The association was most evident for the presence of C. pneumoniae-specific ICs in non-Hodgkin's lymphoma (OR = 7.3, 95% CI 2.2-25) and appeared to be limited to men. Infection with C. trachomatis was found to increase the risk of subsequent development of invasive cervical SCC. Chronic C. pneumoniae infection was also found to be a new independent risk factor for lung cancer in males. Serological markers suggestive of chronic chlamydial infection were associated with lymphomas, proposing that chlamydial infection may have a similar role as H. pylori in the pathogenesis of lymphomas.

Protein A (ProA) chromatography is a bioseparations technique employed throughout the biopharmaceutical industry for the selective capture and purification of IgG-class monoclonal antibodies (mAbs) and Fc-fusion proteins. The rapid growth of mAbs as commercial therapeutics has motivated the need for improved, efficient, and high-throughput purification processes during manufacturing. In direct response, the work presented in thesis aims to 1) increase the scientific community’s understanding of IgG adsorption behavior on ProA chromatography resins and 2) improve the performance of ProA chromatography with ligands that are chemically modified using polyethylene glycol (PEGylated). The results of this thesis suggest that IgG molecules of varying binding strength, or varying elution pH, are capable of competing for binding sites on ProA chromatography resins in simultaneous or sequential adsorption. The competitive phenomenon derives from variance in IgG binding strength, or IgG elution pH, due to differences in sub-class behavior as well as secondary IgG binding interactions with the ProA ligand. Competition is readily apparent in the adsorption of human polyclonal IgG, which has a wide variety of IgG sub-classes and binding epitopes. Additionally, the results presented in this thesis suggest that ProA chromatography resins with PEGylated ligands are a viable path to increase resin robustness and real-world chromatographic selectivity. It is demonstrated that ligand PEGylation can increase resistance to proteolytic digestion, mitigate impurity interactions with mAbs that are bound to ProA, and increase process selectivity against Chinese Hamster Ovary host cell proteins by up to 37%. However, resins with large volumes of conjugated PEG significantly decrease IgG static binding capacity and decrease the available pore space for diffusion, resulting in losses in dynamic binding capacity and productivity. Lighter modifications appear to avoid losses in dynamic binding capacity, however, they do not appear to be effective at mitigating impurity interactions with mAbs that are bound to ProA, which is key to increasing process selectivity. PEGylation of ProA also universally increases the elution pH of IgG molecules by weakening the binding interaction. This last result opens another path of viability for PEGylated ProA ligands for purification of mAbs of Fc-fusion proteins that are sensitive to low pH environments.

No description available.

In animals immunized with 2,4 dinitrophenyl (DNP) hapten-carrier protein conjugates, no in vitro cellular response is elicited by DNP, either alone, or when coupled to a heterologous carrier. In contrast, animals immunized with haptenic peptide-carrier conjugates do mount an in vitro cellular response towards the haptenic peptide. This apparent inconsistency led us to compare the in vivo and in vitro cellular immune responses to a synthetic peptide antigen and its DNP derivative to determine the activation specificity of the cells evoking this response. Guinea pigs were immunized with either the DNP substituted immunogen (DNP-N-10-C) or its unsubstituted form (N-10-C) and subsequent in vivo or in vitro cellular activation was evaluated for DNP alone, DNP coupled to the homologous determinant, and DNP coupled to heterologous carriers. The data suggests that in DNP-N-10-C immune guinea pigs, DNP substitution opens a new determinant exhibiting, in antigen reactive cells, a unique specificity towards the DNP moiety as well as a portion of the peptide to which it is conjugated. However the DNP group by itself does not have the configurational requirement to evoke cellular activation. It therefore plays a minor role in activation of the cellular immune response; the major contribution being supplied by the peptide portion of the 'shared' determinant. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Several cellular and subcellular fractions were prepared from Pseudomonas aeruginosa strain PA-7. Those found to be immunogenic in rabbits included a heat-stable lipopolysaccharide, a protein-lipopolysaccharide complex, a cell wall preparation arid a formalin-killed whole cell vaccine. However, a lipopolysaccharide preparation extracted with phenol and water was found to be a poor immunogen in rabbits. The cell wall fraction proved to be the most effective immunogen in terms of the amount of antibody evoked, and of the duration of the serum antibody response. Hyperimmune sera produced against all four antigens were found to contain a mixed population of 2-mercaptoethanol sensitive and 2-mercaptdethanol resistant antibodies. Gel filtration and ion exchange chromatography studies established the presence of both IgM and IgG immunoglobulins in all four types of hyperimmune serum. Whole immune serum, as well as the IgM and IgG serum fractions, afforded passive protection to mice challenged with twenty or more LD₅₀ of viable organisms. There was an indication that the IgG fraction of two of the four serum types provided better protection than did the IgM fraction, but precipitation studies indicated that this may have been due to greater numbers of IgG immunoglobulins. In addition serum containing a high proportion of 2-mercaptoethanol resistant antibody-was found to promote faster clearance of injected bacteria than did serum taken earlier in the response. Immunodiffusion studies indicated that all four antigenic preparations contained at least one common immunogen; moreover, all serum types were able to react with sheep red blood cells coated with the heat-stable lipopolysaccharide preparation in passive hemagglutination and hemolysin tests. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

It was established that antibodies could be evoked in rabbits against ferredoxin purified from cultures of Clostridium pasteurianum and against its performic acid oxidized derivative. The extent of cross-reaction was studied between the two antisera and four related antigens: native ferredoxin, iron-sulfide free ferredoxin, performic acid oxidized ferredoxin, arid S-carboxymethylated ferredoxin. All combinations demonstrated cross reactivity by complement fixation, and in the case of oxidized ferredoxin antiserum, three preparations, native ferredoxin, iron sulfide free ferredoxin, and performic acid oxidized ferredoxin precipitated antibody. The data obtained with these cross-reactivity studies Indicated that the cysteine-containing regions of the ferredoxin molecule were not critically involved as antigenic determinants. The C-terminal region of the protein was considered for further study. This octapeptide was synthesized and tested for its ability to combine with antibody directed against both native ferredoxin and its performic acid oxidized derivative. The peptide exhibited specific binding to both antisera as demonstrated by inhibition of complement fixation and precipitation, and by equilibrium dialysis experiments. It is suggested that C. pasteurianum ferredoxin is antigenic in rabbits, that cysteine residues are not involved in at least two of the antigenic regions of the protein, and that the C-terminal octapeptide is one of the antigenic determinants of this molecule. / Science, Faculty of / Microbiology and Immunology, Department of / Graduate

Thesis (MPH.) -- University of Limpopo, 2015 / Purpose / Aim: To find out determinants affecting adherence to antiretroviral therapy in patients receiving free treatment from the wellness clinic at Bela Bela District Hospital in Limpopo province of South Africa. Objectives: To identify the determinants which affect the adherence to ART treatment among patients living with HIV and AIDS and to determine which of these determinants are significant predictors of adherence among HIV and AIDS patients. Methodology: a descriptive retrospective, quantitative research. Sampling: A population of 800 patients existing in the recording book was retrieved from the patients’ records at the wellness clinic. Out of 800 a sample of 260 was derived using a simple size calculator tool. Analysis: data were analysed by SPSS Windows Version 21.0. Descriptive statistics means and frequencies were calculated. Chi-Square tests were done in order to test the association between variables (such as age groups, gender, weight groups, regimens and WHO stages). Logistic regression was run to assess the effect of different determinants on the adherence to ART (e.g. viral load affected the adherence contrary to age, gender and others). Results: Female (65%) was more compliant to their male counterpart (35%). Most of the patients (47.3%) in the study belonged to the age group 21 to 35 years and only (2.7%) in the age group less or equal to 20 years. Most patients were categorised into WHO stage I (31.2%). Only 9.2% of the patients were categorised into WHO Stage IV. Most of the patients in group 2 (41.3%) had a weight between 40kgs and 54kgs and group 1 (4.2%) with patients whose weight was less than 40kgs. One of the patients has no record on weight. The majority of patients (44.2%) had CD4 count, less or equal to 100. Only 2.7% had CD4 count 300 and more. After 6 months of treatment, 37% of patients had CD4 count from 300 and above; 9.7% of the patients had CD4 countless than 200. For 136 (52.3%) of the patients in the sample the information on CD4 count at 6 xi months was missing. The majority of patients (72.7%) in the sample had low viral load and only (27.3%) of the patients had high viral load. Majority of patients (48.5%) were on New 1a Regimen instead of Regimen 1a (30.8%) because of the side effects the latter has on them. Some patients (11.2%) were on Regimen 1b, followed by patients (8.1%) on Regimen New 1b. The remaining patients were on Regimen 1c, Reg 2 and Truvada (1.6%). Findings: The majority of patients were young females; in the age-group of 21-35 years. This is reproductive age with many challenges: earlier exposed to infection, more vulnerable than males, stigmatisation, rape, fear of isolation. Majority of patients were in the WHO stage 1 and 2. The WHO stage does not depend on the level of CD4 count. It is important to consider the weight of the patient before to initiate the treatment. More than the half patients had a CD4 count required to start with ART. After 6 months they were more adherent. Most of them were on regimen Reg (New 1a) because of less side effects. The findings showed also different types of associations with some variables were significant determinants such as CD4 count had significant associations with gender, viral load, regimen, WHO staging, the p-value was lesser than 0.05. Conclusion: The results showed that viral load was the only determinant affecting adherence in the current study. The number of males in this study population was lower than females from the age group of less than 20 and age group of 21 to 35, and females than males in age group 36 to 50 and 51 or more. The lower infectivity of males is linked to the state of denial and not testing for HIV. The lower number in females can be due to their positive trends to the ART in their old age. The reasons for the low number need to be investigated. Awareness campaigns should be intentioned towards males. There should be publicity about the equality of both male and female genders.

PhD (Microbiology) / Department of Microbiology

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / The in vitro relationship of sialic acids to the A, B, M, N, C, D, and E antigens of the human erythrocyte has been studied by means of the Landsteiner hapten inhibition test with the idea that substances that strongly inhibit anti-D might find practical application in the prevention and treatment of erythroblastosis fetalis. Our results suggest that N-acetyl neuraminic acid (NANA) is a major constituent of the D (Rh0), M, and N agglutinogens, a minor constituent of the A antigen, but is probably not a functional portion of the B, C, and E antigenic structures. [TRUNCATED] / 2031-01-01

Indiana University-Purdue University Indianapolis (IUPUI) / Severe malaria, primarily caused by Plasmodium falciparum infection, is among the leading causes of childhood mortality globally. A key virulence factor and source of antigenic variation and immune evasion during infection is P. falciparum erythrocyte membrane protein 1 (PfEMP1). Encoded for by approximately 60 var genes, this complex protein mediates cytoadherence of infected erythrocytes to the host endothelium and is a prominent immune target for the anti-malarial immune response in children. During severe malaria, specific domains of PfEMP1 that bind to endothelial protein C receptor (EPCR) and intercellular adhesion molecule-1 (ICAM-1) on host endothelial cells, are more prevalently expressed. The interaction of these proteins and infected erythrocytes mediates the sequestration of infected erythrocytes and plays a role in severe malaria pathogenesis. Antibodies to these domains develop over time with exposure to the parasite and are thought to contribute to immunity against severe malaria in children. In this study, whole blood samples from children with different forms of severe malaria, enrolled in two observational prospective cohort studies were used to quantify the expression of PfEMP1 domains using RT-qPCR and to measure the antibody response to PfEMP1 domains via a bead-based multiplex immunoassay. Using these samples, we demonstrated that although the expression of var transcripts encoding PfEMP1 domains was generally similar across children with different forms of severe malaria, the expression of variants encoding specific EPCR-binding domains was associated with thrombocytopenia and severe anemia. The antibody response to PfEMP1 domains in children with severe malaria was highest in children with SMA and children with asymptomatic parasitemia, but not associated with decreased risk of additional malaria episodes. Overall, the results of this study suggest that PfEMP1 is acting similarly across different forms of severe malaria but that it can be related to pathogenesis and severe malaria immunity.