Biomedical subjects
Barbara McGovern
Publications and source records attributed to Barbara McGovern.
Broad repertoire of the CD4+ Th cell response in spontaneously controlled hepatitis C virus infection includes dominant and highly promiscuous epitopes.
A vigorous hepatitis C virus (HCV)-specific Th cell response is regarded as essential to the immunological control of HCV viremia. The aim of this study was to comprehensively define the breadth and specificity of dominant HCV-specific CD4(+) T cell epitopes in large cohorts of subjects with chronic and spontaneously resolved HCV viremia. Following in vitro stimulation of PBMC, HCV-specific cell cultures from each subject were screened with an overlapping panel of synthetic 20-mer peptides spanning the entire HCV polyprotein. Of 22 subjects who spontaneously controlled HCV viremia, all recognized at least one of a group of six epitopes situated within the nonstructural (NS) proteins NS3, NS4, and NS5, each of which was detected by >30% of subjects, but most subjects recognized additional, more heterogeneous specificities. In contrast, none of the most frequently targeted epitopes was detected by >5% of persons with chronic infection. The most frequently recognized peptides showed promiscuous binding to multiple HLA-DR molecules in in vitro binding assays and were restricted by different HLA-DR molecules in functional assays in different persons. These data demonstrate that predominant CD4(+) T cell epitopes in persons with resolved HCV infection are preferentially located in the nonstructural proteins and are immunogenic in the context of multiple class II molecules. This comprehensive characterization of CD4(+) T cell epitopes in resolved HCV infection provides important information to facilitate studies of immunopathogenesis and HCV vaccine design and evaluation.
Delivering therapy for hepatitis C virus infection to incarcerated HIV-seropositive patients.
The increase in morbidity and mortality due to end-stage liver disease has fueled recent guidelines that recommend consideration of treatment for hepatitis C in human immunodeficiency virus (HIV)-infected patients. Unfortunately, studies indicate that few patients coinfected with HIV and hepatitis C virus (HCV) are treated for their underlying hepatitis because of ongoing substance abuse, depression, chaotic lifestyles, homelessness, and perceived nonadherence. The structured environment of the prison system enables clinicians to provide complicated therapies for HCV to HIV-infected patients in combination with substance abuse programs. Furthermore, adherence to and adverse effects of therapy can be closely monitored. Offering treatment for HCV infection during incarceration to HIV-seropositive persons is highly efficient and targets underserved minority patients who have limited access to care in the community.
Response to hepatitis B vaccine in HIV-1-positive subjects who test positive for isolated antibody to hepatitis B core antigen: implications for hepatitis B vaccine strategies.
BACKGROUND: Whether human immunodeficiency virus type 1 (HIV-1)-positive subjects who test positive for isolated antibody to hepatitis B core antigen (anti-HBc) should be vaccinated with hepatitis B vaccine is not certain. Development of an anamnestic response after vaccination would suggest previous hepatitis B virus (HBV) infection, in which case vaccination is not necessary. METHODS: Sixty-nine HIV-1-positive subjects who tested negative for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) received vaccination with standard hepatitis B vaccine. Twenty-nine subjects (42%) tested positive for anti-HBc, and 40 (58%) tested negative for anti-HBc. An anamnestic response was defined as an anti-HBs titer of >or=10 IU/L within 4 weeks of the first vaccination. RESULTS: The overall anamnestic response rate was 16% and was not significantly different between subjects who tested positive for anti-HBc (24%) and those who tested negative for anti-HBc (10%) before vaccination (P=.18). Approximately 50% of subjects who tested positive for anti-HBc also tested positive for antibody to hepatitis Be antigen (anti-HBe). The anamnestic response rate was higher in subjects who tested positive for both anti-HBc and anti-HBe (43%) than in subjects who tested positive for anti-HBc but negative for anti-HBe (7%) (P=.035). After a complete series of vaccinations, HIV-1/hepatitis C virus (HCV)-coinfected subjects were less likely to achieve high anti-HBs titers than were subjects infected with HIV-1 alone. CONCLUSIONS: After hepatitis B vaccination, the anamnestic response rate in HIV-1-positive subjects who tested positive for isolated anti-HBc but negative for anti-HBe was low and was comparable to that in subjects who tested negative for anti-HBc. This finding suggests that testing for anti-HBc alone may not be a reliable assessment of protection from HBV infection. HIV-1/HCV coinfection may be associated with impaired responses to hepatitis B vaccine, and evaluation of strategies to improve immunogenicity of the vaccine in such individuals is warranted.
What drives hepatitis B virus-related hepatic flares? Virus, T cells--or a bit of both?
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Hepatic safety and HAART.
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Low prevalence of ongoing hepatitis B viremia in HIV-positive individuals with isolated antibody to hepatitis B core antigen.
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Should treatment of hepatitis C in HIV-seropositive and HIV-seronegative patients with hemophilia include induction doses of interferon?
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Isolated antibody to hepatitis B core antigen in human immunodeficiency virus type-1-infected individuals.
We screened 651 human immunodeficiency virus (HIV)-1-infected subjects for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBs). Of a total of 387 subjects who tested negative for both HBsAg and anti-HBs, 142 underwent further testing for isolated presence of antibody to hepatitis B core antigen (anti-HBc). Of these 142 subjects, 60 (42%) tested positive for anti-HBc (isolated anti-HBc). Individuals coinfected with HIV-1 and hepatitis C virus (HCV) were more likely to have isolated anti-HBc than were subjects with HIV-1 alone (80% vs. 16%, respectively). Our findings suggest that individuals with HIV-1/HCV coinfection for whom there is no serological evidence for hepatitis B virus when screened with HBsAg and anti-HBs will be positive for anti-HBc in >75% of cases. A screening strategy that tests only for HBsAg and anti-HBs in HIV-1-infected patients will miss a large number of individuals with isolated anti-HBc.
Antiretroviral drug resistance mutations in antiretroviral-naive prisoners.
We assessed the incidence of antiretroviral drug resistance in a cohort of 25 antiretroviral-naive, human immunodeficiency virus-positive inmates in Massachusetts. Silent mutations, unexpected mutations at resistant sites, and resistance mutations were recorded. Among these inmates, we found a prevalence of drug resistance mutations that was equivalent to the prevalence previously found in nonprison populations in the same state.
Risk of HAART therapy in hepatitis C.
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Evaluation and treatment of the HIV/HCV coinfected patient: a case history and discussion.
Declining rates of morbidity and mortality related to opportunistic infections in the era of highly active antiretroviral therapy (HAART) have led to a new focus on hepatitis C (HCV). Several studies suggest that the natural history of HCV is accelerated in patients with HIV infection. Recent literature highlights higher rates of fibrosis progression and increasing rates of morbidity and mortality related to end-stage liver disease. As a result, more and more clinicians are turning their attention to the evaluation and management of hepatitis C in an effort to prevent or slow down the progression to advanced liver disease. The following case history illustrates many of the complicated steps in the evaluation process of these patients. Several important issues are discussed, such as the rationale in performing a liver biopsy, when to initiate treatment, drug interactions, and adverse effects of therapy.
Broad specificity of virus-specific CD4+ T-helper-cell responses in resolved hepatitis C virus infection.
Vigorous virus-specific CD4+ T-helper-cell responses are associated with successful control of hepatitis C virus (HCV) and other human viral infections, but the breadth and specificity of responses associated with viral containment have not been defined. To address this we evaluated the HCV-specific CD4+ T-helper-cell response in HCV antibody-positive persons who lack detectable plasma viremia, and compared this response to that in persons with chronic HCV infection. Peripheral blood mononuclear cells were stimulated with HCV proteins, followed by measurement of HCV-specific CD4+ T-cell responses to a comprehensive set of overlapping HCV peptides by intracellular gamma interferon production. In three persons with resolved HCV infection studied in detail, 13 to 14 epitopes were targeted, but none was recognized by all three. The 37 defined epitopes were predominantly distributed among the HCV proteins core, NS3, NS4, and NS5. In an expanded analysis of responses to these proteins in persons with resolved infection, an average of 10 epitopes was targeted, whereas in persons with chronic viremia never was more than one epitope targeted (P < 0.001). This comprehensive analysis of the breadth and specificity of HCV-specific T-helper-cell responses indicates that up to 14 viral epitopes can be simultaneously targeted by circulating virus-specific CD4+ T helper cells in a controlled human viral infection. Moreover, these data provide important parameters for evaluation of candidate HCV vaccines, and provide rationale for immunotherapy in chronic HCV infection.