Peter Lundholm

Induction of mucosal IgA by a novel jet delivery technique for HIV-1 DNA.

Novel ways of delivering plasmid DNA to elicit humoral IgA, IgG and cell-mediated immune responses in mice were investigated. Intraoral administration of DNA in the cheek, using a jet immunization technique, elicited the highest IgA mucosal responses. Intranasal immunization gave strong mucosal IgA responses and persistent systemic IgG. Immunoglobulin isotype analysis revealed an IgG1 profile for intramuscular tongue and gene gun immunizations and an IgG2a profile following oral jet injection and intranasal application. The route of delivery was of importance for the characteristics and quality of the mucosal immune response following DNA immunization. For DNA vaccine delivery, the intraoral jet injection technique has the advantages of being a simple and rapid way of administering the DNA in solution and of provoking specific mucosal IgA when administered in the mucosal associated lymphoid tissue.

Nucleic acid vaccination with HIV regulatory genes: a combination of HIV-1 genes in separate plasmids induces strong immune responses

The concept of combining several genes in order to immunize against a microbial agent has been tested. We selected human immunodeficiency virus (HIV) genes that individually have been shown to mediate immune responses against HIV proteins. These proteins were the regulating genes/proteins of HIV-1 rev, tat and nef as well as structural genes for gp160 under the control of rev, and the capsid p24 represented by the larger precursor gene p37. Two findings were of particular interest. The combination of these five gene constructs gave strong reactivity to all of them, compared with previous results using each one in single injections. The intranasal immunization route gave good mucosal reactivity by inducing IgG, IgA and T-cell proliferative responses.

DNA mucosal HIV vaccine in humans

This is a demonstration of immune activation by delivery of genetic vaccines in human mucosa. We analyzed the local and systemic responses in HIV-1 infected individuals following intraoral jet-injections of HIV-1 DNA constructs encoding the nef, rev, and tat regulatory genes. The immunological responses of the oral mucosa may be representative of other mucosal sites and was therefore selected for induction of mucosal reactivity by DNA immunization. The oral and intramuscular routes induced specific systemic T cell proliferative responses. Immunohistochemical analysis of oral biopsies 2 days after immunization revealed increased levels of granulocytes and T cells as well as expression of HLA-DR. T cell markers for CD3 +, CD4 + and CD8 + were significantly increased in the vaccinated mucosa. Vaccine-specific local and systemic antibodies were present during the immunization. However, increases were neither seen in the local or systemic titer nor in the B-cell accumulation in response to the immunizations. The presence of HIV-1 plasmid DNA was observed in mucosal biopsies as well as local proinflammatory T lymphocyte immune responses with predominantly IL-2 expression in the oral mucosal transudate.

DNA-plasmids of HIV-1 induce systemic and mucosal immune responses.

Abstract DNA-based immunization has been shown to induce protective immunity against several microbial pathogens including HIV-1. Several routes of DNA vaccination have been exploited. However, the properties of the immune responses seem to differ with the different routes used for DNA delivery, ultimately affecting the outcome of experimental challenge. We measured the primary immune response following one vaccination. This report presents differences associated with three different DNA delivery routes: intramuscular injection, intranasal application, and gene-gun based immunization. Induction of systemic humoral immune responses was achieved most efficiently by either intranasal or gene-gun mediated immunization, followed by intramuscular injection. Mucosal IgA was reproducibly induced by intranasal instillation of the DNA, and found in lung washings, faeces, and vaginal washings. Cytotoxic T cells were not induced by a single immunization, but were observed after three immunizations using intramuscular injections.

Genetic Immunization with Multiple HIV-1 Genes Provides Protection against HIV-1/MuLV Pseudovirus Challenge in vivo

Superinfection by HIV-1 of a cell line containing the complete murine leukemia virus (MuLV) genome was shown to give rise to pseudotyped HIV-1/MuLV. Such superinfection was successful with certain strains of HIV-1 subtypes A–D. Primary spleen cells and cells of the peritoneal cavity of immunocompetent mice of the C57Bl/6 strain were infectable with the pseudotype HIV-1/MuLV and secreted HIV-1 in vitro and in vivo. In contrast, the murine cell lines, NIH 3T3, myeloma cell line Sp2/0, and two murine hybridoma cell lines were relatively resistant to infection and produced no or little HIV. After primary murine spleen cells had been infected with pseudotyped HIV-1 and transferred to C57Bl/6 mice, replication-competent HIV-1 was obtained from the peritoneal cavity for at least 10–14 days. High amounts (>105 vRNA copies/ml) of HIV-1 vRNA could be measured in the peritoneal fluid. Presence of HIV-1 proviral DNA was detectable in cells from the peritoneal cavity for up to 24 days after infected cell transfer. Active reverse transcriptase representing both HIV-1 and C-type murine retroviruses was detected in the peritoneal washes. The HIV-infected spleen cells injected into the peritoneal cavity elicited HIV-1-specific cellular immune responses to p24gag, gp160Env, Nef, Tat and Rev. Mice immunized with HIV-1 DNA, but not with HIV-1 protein, cleared their HIV-1-infected cells within 10–14 days after challenge with HIV-1/MuLV-infected syngeneic spleen cells. This novel model system of primarily cellular reactivity to HIV-1-infected cells in vivo may become useful for assaying experimental HIV-1 immunization schedules.

Autoreactivity in HIV-infected individuals does not increase during vaccination with envelope rgp160

The HIV-1 envelope protein contains several regions with amino acid homology to HLA class I and class II molecules. We evaluated possible changes in antibody responses to those regions during vaccination with rgp 160 produced in a baculovirus system. Forty asymptomatic HIV-infected patients with CD4 cell counts above 400 were vaccinated with rgp 160. Twenty-one patients were tissue-typed as HLA A2. Sixty-two percent of these patients exhibited cytotoxic lymphocyte antibodies directed to CD8+, HLA A2 cells. This cytotoxicity decreased during HIV gp160 vaccination. In order to further characterize the specificity of these responses, analogues of HLA class I and HLA-DR peptides were chemically synthesized together with their correct HIV-1 gp160 sequences. Enzyme-linked immunosorbent assays (ELISA) with sera from before, during and after immunization were performed with HIV proteins, peptides and their homologues. All patients showed an increase in their previously poor specific T-cell activation to gp160. Fourteen patients developed increased avidities or titres to HIV proteins and/or peptides. Contrarily, serum IgG titers to the HLA homologous peptides were initially low and decreased further during the course of vaccination. This decrease occurred in the majority of patients, 35-40 of the 40 individuals, depending on the antigen. Independent measures of autoantibodies to Ro/SS-A and La/SS-B remained undetectable.

Immunoglobulin G abnormalities in HIV-1 infected individuals with lymphoma.

BACKGROUND Polyclonal B-cell activation precedes the occurrence of malignant B-cell clones. Several recent reports suggest a perturbed cytokine regulation in HIV-related lymphomagenesis and Epstein-Barr virus (EBV) involvement in approximately half of the cases with generalized lymphoma. OBJECTIVES We investigated whether altered immunoglobulin properties would be detected by fine analysis of the immunoglobulin G (IgG) subclass patterns against HIV and EBV epitopes. STUDY DESIGN HIV-1 infected patients in early stage, late stage and with lymphoma were analyzed by ELISA for anti HIV and EBV IgG class and subclass antibodies. Avidity and affinity of the antibodies were studied. The lymphoma patients were also studied by PCR for EBV DNA in serum. RESULTS The total IgG reactivity to several HIV antigens was similar in the three patient groups. However, lymphoma patients had a more restricted subclass pattern with significantly lower IgG1 and IgG3 anti gp120 titers compared to other HIV-infected patients but good and persistent total IgG and IgG1 (excluding the gp120 antigen) reactivities in contradiction to their low CD4 counts. IgG4 reactivity was sparse, detectable to significant levels in the symptomatic group only. The observed relative affinity of the HIV-specific IgG and IgG1 of lymphoma patients was similar to that of asymptomatic and symptomatic patients. The subclass reactivity to the EBV peptide was similar in all groups but lymphoma patients with EBV DNA in serum exhibited significantly lower anti EBV peptide titers than those who were EBV DNA negative. CONCLUSION These findings indicate that subclass analysis to defined viral antigens may be a means to detect immune dysregulation in tumor development.