David Looney

HIV gp120-specific cell-mediated immune responses in mice after oral immunization with recombinant Salmonella

Salmonella is of great interest as a potential human immunodeficiency virus vaccine vector because of its ability to elicit potent mucosal and systemic immune responses when administered orally. To determine whether such a vaccine could elicit an immune response in mice, plasmids expressing HIV gp120-LAI were introduced into attenuated S. typhimurium. Three serial doses of 10(10) recombinant organisms were administered orally to BALB/c mice at 2-week intervals. Immunized mice but not control mice demonstrated proliferative T cell responses to gp120-LAI, comparable in magnitude to the proliferative responses to Salmonella antigens. Immunized mice had detectable serum and intestinal Salmonella-specific IgA and serum Salmonella-specific IgG. However, no gp120-specific antibody was detected in either serum or intestinal washes. These results indicate that live recombinant Salmonella-based vaccine constructs can induce HIV-specific cellular immune responses in vivo.

Herpes simplex virus type 2 acquisition during recent HIV infection does not influence plasma HIV levels.

We assessed the effect of herpes simplex virus type 2 (HSV-2) acquisition on the plasma HIV RNA and CD4 cell levels among individuals with primary HIV infection using a retrospective cohort analysis. We studied 119 adult, antiretroviral-naive, recently HIV-infected men with a negative HSV-2-specific enzyme immunoassay (EIA) result at enrollment. HSV-2 acquisition was determined by seroconversion on HSV-2 EIA, confirmed by Western blot analysis. Ten men acquired HSV-2 infection a median of 1.3 years after HIV infection (HSV-2 incidence rate of 7.4 per 100 person-years of follow-up). The median time of follow-up after acquiring HSV-2 infection was 303 days. All men except 1 were asymptomatic during HSV-2 acquisition, and only 1 HSV-2 seroconverter, who was asymptomatic, had a transient increase in blood HIV load (0.5 log10 copies/mL over 11 days). The HSV-2 incidence rate was high in our cohort of recently HIV-infected individuals; however, HSV-2 acquisition did not significantly change the plasma HIV dynamics and CD4 cell levels.

Evaluation of a Highly Sensitive Qualitative Human Immunodeficiency Virus Type 1 (HIV-1) RNA Assay for Detection of HIV-1 Suppression

By using a mathematical model, the APTIMA human immunodeficiency virus type 1 (HIV-1) RNA qualitative assay was evaluated as a semiquantitative assay to distinguish HIV-1 patient samples needing quantitation from samples in which the virus was suppressed with antiretroviral therapy.

Differences in Tuberculin Reactivity as Determined in a Veterans Administration Employee Health Screening Program

ABSTRACT In response to a difference in pricing, the San Diego Veterans Administration Medical Center changed its tuberculin preparation from Tubersol to Aplisol in the fall of 2006. Following the change, an increased number of employee skin test conversions was noted. Employee tuberculin skin test converters from 2006 were screened with the QuantiFERON Gold (QFT-G) gamma interferon release assay. Those employees who tested negative by QFT-G were asked to repeat their skin test with both Tubersol and Aplisol tuberculin preparations. Of the new purified protein derivative converters, 12 of 14 returned for repeat testing with QFT-G, and the assay was negative for 83% (10/12), positive for 8% (1/12), and indeterminate for 8% (1/12) of the individuals. Nine of the individuals who were QFT-G negative agreed to repeat skin testing with both tuberculin preparations, and 7/8 (87.5%) demonstrated reactivity with the Aplisol preparation, while 0/8 (0%) reacted to the Tubersol preparation. A change from Tubersol to Aplisol resulted in elevated tuberculin skin test conversion rates that may be due to false-positive reactions. The differences in skin test reactivity between preparations support CDC guidelines that recommend that institutions should not change tuberculin preparations, as doing so may falsely increase the number of positive reactions.