Cytokine-containing liposomes as adjuvants for HIV subunit vaccines

Dehydration-rehydration liposome vesicles (DRVs) containing various cytokines were evaluated for their ability to induce delayed-type hypersensitivity (DTH) and humoral immunity to the recombinant envelope protein rgp120 of the MN strain of human immunodeficiency virus type 1 (HIV-1). The DRVs trapped approximately 25% of the radiolabeled cytokines and approximately 17% of the radiolabeled rgp120 that were added. The level of trapping was greater than the aqueous volume of the DRVs, indicating association of the proteins with the lipid bilayer. Flow cytometric analysis using antibody to rgp120 or the V3 loop of rgp120 showed the diameter of the DRVs to be 2-7.5 microns. Transmission electron microscopy confirmed the heterogeneity in size of the DRVs and revealed morphological heterogeneity. Transmission electron microscopy with immunogold labeling also revealed the presence of rgp120 on the surface of the DRVs. In vitro bioassays demonstrated slow leakage of biologically active cytokines from DRVs soaked in tissue culture medium containing serum. Mice injected subcutaneously three times at 14-day intervals with DRVs containing 15 micrograms of rgp120 plus interleukin 6 (IL-6) or interferon gamma (IFN-gamma) produced significantly greater DTH responses than mice injected with DRVs containing rgp120 alone. Soluble rgp120 plus soluble IFN-gamma produced DTH in some experiments, but of lower magnitude than the comparable DRVs. Interleukin 6, but not IFN-gamma, increased the antibody titer to rgp120 when included in the DRVs. The mice did not develop antibodies to IFN-gamma or IL-6. Induction of DTH by vaccines may increase protection from viral pathogens such as HIV. Cytokine-containing liposomes may be an effective adjuvant for the induction of a DTH response to envelope-antigen subunit vaccines.

Cloning and genetic characterization of the human kinesin light-chain (KLC) gene

We report the isolation, sequence, and identification of a cDNA encoding the human kinesin light-chain (KLC) protein. The cDNA molecule consisted of 276 nucleotides of 5' untranslated region, the complete coding sequence of 1,710 nucleotides, and 322 nucleotides of 3' untranslated region. It encoded a polypeptide of 569 amino acids and a deduced molecular mass of 64,789 daltons. The predicted secondary internal structure of the KLC molecule consisted of about 27 contiguous repeats, each of approximately 21 amino acid residues, and could be divided into three domains. The amino-terminal domain consisted of heptad repeats typical of the rod domain of several cytoskeletal proteins. The central and carboxy-terminal domains consist of 21-mer repeats. KLC mRNA was expressed in most tissues analyzed. The gene, which was expressed in bacteria and Chinese hamster ovary cells, was provisionally assigned to the long arm of human chromosome 14.

Interleukin 1 of the central nervous system is produced by ameboid microglia

By screening specific populations of rat brain cells, we found that ameboid microglia secrete an 18 kD peptide with IL-1 biological activity. The IL-1 activity released by microglia was found to be identical to rat macrophage IL-1 on fractionation by gel filtration and high pressure liquid anion-exchange chromatography, and it was neutralized by an antiserum specific for murine IL-1. When added to astroglia grown in culture, microglial IL-1 increased the cell number of five- to sevenfold, and increased astroglial incorporation of [3H]thymidine by three- to fivefold. We propose that the proliferation of astroglia in specific brain regions may be regulated by the signaled release of IL-1 from activated microglial cells.

3,4,3',4'-tetrachloroazobenzene: a potential environmental toxicant

3,4,3',4'-tetrachloroazobenzene (TCAB), a potential environmental toxicant formed in the industrial manufacturing and the microbial degradation of chloroanilide herbicides, has been prepared in 87% yield by an improved procedure. In vitro experiments with C3H/10T1/2 cells have shown that TCAB is toxic to mammalian cells, which may be correlated with observable cytological changes. TCAB has also been found to be weakly mutagenic by the Salmonella/microsome test. In addition, C3H/10T1/2 cells are transformed following a ten day incubation with TCAB. These data suggest the potential health hazard associated with the environmental occurrence of TCAB.