Boosting of ALVAC-SIV vaccine-primed macaques with the CD4-SIVgp120 fusion protein elicits antibodies to V2 associated with a decreased risk of SIVmac251 acquisition

The recombinant ALVAC vaccine coupled with the monomeric gp120/alum protein have decreased the risk of HIV and SIV acquisition. Ab responses to the V1/V2 regions have correlated with a decreased risk of virus acquisition in both humans and macaques. We hypothesized that the breadth and functional profile of Abs induced by an ALVAC/envelope protein regimen could be improved by substituting the monomeric gp120 boost, with the full-length single-chain (FLSC) protein. FLSC is a CD4-gp120 fusion immunogen that exposes cryptic gp120 epitopes to the immune system. We compared the immunogenicity and relative efficiency of an ALVAC-SIV vaccine boosted either with bivalent FLSC proteins or with monomeric gp120 in alum. FLSC was superior to monomeric gp120 in directing Abs to the C3 a2 helix, the V5 loop, and the V3 region that contains the putative CCR5 binding site. In addition, FLSC boosting elicited significantly higher binding Abs to V2 and increased both the Ab-dependent cellular cytotoxicity activity and the breadth of neutralizing Abs. However, the FLSC vaccine regimen demonstrated only a trend in vaccine efficacy, whereas the monomeric gp120 regimen significantly decreased the risk of SIVmac251 acquisition. In both vaccine regimens, anti-V2 Abs correlated with a decreased risk of virus acquisition but differed with regard to systemic or mucosal origin. In the FLSC regimen, serum Abs to V2 correlated, whereas in the monomeric gp120 regimen, V2 Abs in rectal secretions, the site of viral challenge, were associated with efficacy. The Journal of Immunology, 2016, 197: 2726-2737

Reconstitution of long-term T helper cell function after zidovudine therapy in human immunodeficiency virus-infected patients

Peripheral blood mononuclear cells from 12 asymptomatic patients infected with human immunodeficiency virus (HIV) and 4 patients with AIDS were analyzed before and during therapy with zidovudine for T helper cell (Th) function. Th function improved by more than fourfold to one or more of three stimuli tested in 9 (75%) of 12 asymptomatic patients on zidovudine therapy and in 3 of 4 patients with AIDS. Only 6 (7.4%) of 80 untreated HIV-infected control patients showed spontaneous improvement in Th function (P 1 year after start of therapy in 6 patients and for > 2 years in 2 patients. No correlation was observed between improved Th function and changes in CD4+ or CD8+ cell numbers or in levels of serum HIV p24 antigen or \u3b22-microglobulin. These results suggest inclusion of in vitro Th function as a useful marker in determining the efficacy of antiretroviral drug therapy of HIV-infected patients

Multiple defects of T helper cell function in newly diagnosed patients with Hodgkin's disease

T helper cell (TH) function, as assessed by interleukin-2 (IL-2) production and [3H]thymidine incorporation, was studied in 47 newly diagnosed untreated patients with Hodgkin's disease (HD) and 34 healthy controls. Three different stimuli were used to stimulate in vitro peripheral blood mononuclear cells (PBMC): influenza A vaccine (FLU), HLA alloantigens (ALLO) and phytohaemagglutinin (PHA). Four different patterns of TH function were observed in HD patients: (1) IL-2 production in response to all of the stimuli (40%); (2) IL-2 production in response to ALLO and PHA but not to FLU (26%); (3) IL-2 production in response to PHA alone (19%); and (4) failure to respond by IL-2 production to any of the three of the stimuli (15%). Thus, defective in vitro TH function was detected in the majority of these patients (60%). Defective TH function was observed in none of the 34 controls. Severely compromised TH function (patterns 3 and 4) tended to be associated with more advanced clinical presentation and more compromised haematological parameters (P < 0.05). The IL-2 production assay was more sensitive than the proliferative assay as only 30% of the HD patients failed to proliferate in response to FLU, and none failed to proliferate in response to either ALLO or PHA; this assay can detect subtle, multiple patterns of immune dysregulation in untreated HD patients. Our results suggest that HD is associated with a fundamental dysregulation in TH function, illustrate the complexity of such dysregulation, and raise the possibility that HD progression will be associated with a type-1-type-2 switch in immunoregulatory cytokine production

Cellular immune factors associated with mother-to-infant transmission of HIV

Objective: To study a possible correlate of protection in mother-to-infant transmission of HIV infection. In particular, to determine whether lack of HIV-specific T-helper (TH) function as indicated by HIV and non-HIV antigen-stimulated interleukin (IL)-2 production of mother and/or newborn peripheral blood leukocytes (PBL) is associated with mother-to-infant transmission of HIV. Methods: PBL from 21 HIV-seropositive pregnant women and 23 cord blood leukocytes (CBL) from their offspring were studied for in vitro TH function by IL-2 production in response to HIV and non-HIV antigens. Polymerase chain reaction (PCR) and viral culture assays were performed to determine HIV infection of the infants. Results: PBL from 10 out of 21 (48%) mothers and from eight out of 23 (35%) CBL samples responded to two or more out of five synthetic gp160 envelope (env) peptides. Three of the 23 (13%) offspring were shown to be HIV-infected by PCR and/or viral culture on follow-up. All three infected infants were from a subset whose CBL did not exhibit env-specific TH immunity. Conclusion: Our results demonstrate that fetal T cells can be primed to HIV env determinants in utero, suggest that HIV-specific TH immunity may be protective in newborns, and provide a possible means for identifying newborns who are at risk for HIV infection

Pilot study of the immunologic effects of recombinant human growth hormone and recombinant insulin-like growth factor in HIV-infected patients

Objective: To study the immunologic effects of recombinant human growth hormone (rhGH), recombinant human insulin-like growth factor type 1 (rhIGF-1), or the combination, in patients with moderately advanced HIV infection. Design: Randomized but not blinded trial. Setting: Government medical research center. Patients: Twenty-four HIV-infected patients with CD4 cell counts of 100-400 x 106/l who were receiving nucleoside antiretroviral therapy. Interventions: Either rhGH, rhIGF-1, or the combination was administered subcutaneously for 12 weeks. Main outcome measures: Immunologic parameters, including T-cell subsets and assays of in vitro interleukin (IL)-2 production in response to antigens and mitogens, and safety profile. Results: Plasma IGF-1 levels were low or low-normal prior to treatment and increased with all three therapies. There were no significant changes in CD4 cell counts, RA/RO CD4 cell subsets, natural killer cell function, immunoglobulin levels, or in vitro IL-2 production in response to mitogen or alloantigens. However, there was an upward trend (and for p18(IIIB) a statistically significant increase) in the in vitro IL-2 production in response to each of five HIV envelope peptides. Potential toxic effects included fatigue, arthralgia, edema, myalgia, and headache. Patients also were noted to have weight gain averaging 4 kg early in the course of treatment. Conclusions: These results suggest that treatment with rhGH/rhIGF-1 was reasonably well tolerated and that modest improvement in HIV-specific immune function was attained. Further studies will help clarify the therapeutic potential of rhGH/rhIGF-1 as an immunostimulator in the setting of HIV infection