HIV-Specific CD4⁺and CD8⁺Immune Responses Are Generated with a gp120-Depleted, Whole-Killed HIV-1 Immunogen with CpG Immunostimulatory Sequences of DNA

Abstract

We examined the adjuvant effects of a synthetic CpG oligodeoxynucleotide immunostimulatory sequence (ISS) using a whole-killed, gp120-depleted HIV antigen (HIV-1 antigen) in a Lewis rat model. We hypothesized that HIV-1-specific CD4(+) T helper (Th) immune responses could be enhanced when an ISS was combined with an HIV-1 antigen in incomplete Freund's adjuvant (IFA). We also reasoned that if such Th responses were sufficient, such a combination might also induce HIV-specific CD8(+) T cell immune responses. Here we demonstrate that the HIV-1 antigen in IFA combined with ISS stimulates both CD4(+) and CD8(+) HIV-specific immune responses as measured by interferon-gamma (IFN-gamma) in the ELISPOT assay. A strong correlation between these CD4(+) and CD8(+) responses was demonstrated. Furthermore, we found that the HIV-1 antigen in IFA with ISS as an adjuvant stimulated strong antibody responses to core antigen (p24). These studies suggest that the combination of the whole-killed, gp120-depleted HIV-1 antigen in IFA with ISS may be an ideal candidate to test in nonhuman primates and in human studies as a preventive HIV-1 vaccine.

Optimal Thawing of Cryopreserved Peripheral Blood Mononuclear Cells for Use in High-Throughput Human Immune Monitoring Studies

“…This was the first study to systematically assess the effect of cryopreservation on T cell functionality using ELISPOT: a key finding from this study was that the addition of chilled washing medium to chilled cells can be highly detrimental to PBMC viability (Figure 1 in that publication). ELISPOT provides a reliable quantitative approach to assess functionality of diverse immune cell types including T cells of both CD4 and CD8 lineages [29,30,31]. We and others have utilized ELISPOT effectively to assess immunogenicity of both candidate- and licensed vaccines [5,26,32].…”

Synergistic Effect of Combined HIV/HCV Immunogens: A Combined HIV-1/HCV Candidate Vaccine Induces a Higher Level of CD8+ T Cell-Immune Responses in HLA-A2.1 Mice

“…Montanide ISA-51 is a mineral oil based adjuvant and has been shown to increase immune responses nonspecifically [2,34]. CpG-ODN is also among the most frequently used experimental adjuvant; this adjuvant stimulates dendritic cells through Toll-like receptor (TLR) 9, inducing cell maturation and enhancing antigen presentation and Th1 responses [25,26,38]. In addition, CpG-ODN up-regulates the expression of TAP (transporter associated with antigen presentation) in a type I interferon-dependent manner, resulting in induction of CTL responses independently of CD4+T cells [20].…”

Maternal and newborn immunization with a human immunodeficiency virus‐1 immunogen in a rodent model

“…It is well known that cytosine‐phosphorothioate‐guanine dinucleotide (CpG) ISS of DNA are naturally occurring unmethylated nucleotide sequences shown to stimulate B cells, dendritic cells and macrophages 6 . These sequences have been used, either alone or in combination with various adjuvants, to stimulate strong CD4 T helper immune responses 7 as well as CD8 T‐cell responses 2,8 . Multiple studies suggest that cell‐mediated immune responses, which include IFN‐γ production, cytotoxic T lymphocytes (CTLs) and CD8 antiviral suppressive factors, including β‐chemokines, may be associated with slower disease progression and prevention of disease 9–13 .…”

“…A vaccine may have an important role in preventing pediatric human immunodeficiency virus‐1 (HIV‐1) infection if protective immunity can be established during the neonatal period. It has previously been demonstrated that the combination of a gp120‐depleted, whole‐killed antigen in incomplete Freund's adjuvant (IFA) with immunostimulatory sequences (ISS) was a more potent stimulator of an antigen‐specific T helper 1 (Th1) type immune response and β‐chemokines than antigen and ISS or antigen and IFA 1–3 . We hypothesized that a protective immune response in the neonate might require maternal immunization, in order to develop passive antibody‐mediated immunity, followed by neonatal immunization, in order to induce cell‐mediated immune responses.…”