SIV vaccine protection of rhesus monkeys.

Rhesus macaques (M. mulatta), immunized with an inactivated whole SIVmac vaccine and muramyl dipeptide or Freund's incomplete adjuvant, were protected against IV challenge infection with 10 animal infectious doses of the homologous virus. The protection in these animals appeared to be complete, with no breakthrough of latent virus infection over a 10-month period. Vaccine protection in this model was correlated generally with a high level of SIVmac envelope antibody by ELISA and immunoblot, high titers of syncytial inhibiting antibody, and, more specifically, with the presence of antibodies binding to a putative V3 loop synthetic peptide of the SIVmac outer envelope. This model can now be used for further identification of the protective epitopes and protective host immune responses as well as for development of novel and better AIDS vaccines.     

Evaluation of protective efficacy of recombinant subunit vaccines against simian immunodeficiency virus infection of macaques.

Simian immunodeficiency virus (SIV) was used as a model to study the protective efficacy of an immunization regimen currently being evaluated as candidate vaccines against HIV in human subjects. Four Macaca fascicularis were first immunized with recombinant vaccinia virus expressing the envelope glycoprotein gp160 of SIVmne and then boosted with subunit gp160. Both cell-mediated and humoral immune responses against SIV, including neutralizing antibodies, were elicited. The macaques were shown to be protected from a homologous virus infection as determined by serology, lymphocyte cocultivation, polymerase chain reactions and in vivo transmission analyses. Four unimmunized control animals were readily infected. However, viremia in infected control animals could decrease substantially following the initial phase of infection so that persistent infection might not be readily detectable.     

Fluorescence quenching of methyl-2-aminobenzoate in the presence of beta-cyclodextrin: A model for the dynamic quenching of chromophores in hydrophobic regions of biopolymers

The binding constant of methyl-2-aminobenzoate to beta-cyclodextrin was determined by fluorescence titration to be 92.1M^?1 at 25°C in pH 7 buffer. Beta-cyclodextrin dramatically protects methyl-2-aminobenzoate against quenching by iodate and protects, though much less efficiently, against the smaller quencher, iodide. The observed decrease in fluorescence lifetime of the methyl-2-aminobenzoate-beta-cyclodextrin complex on addition of quencher indicates that the quenching mechanism is collisional (dynamic). The dependence of quenching rate on solvent viscosity is less than expected from simple theoretical considerations. However, the extent of beta-cyclodextrin protection is essentially viscosity-independent. These model studies show the usefulness of iodate as a quencher and encourage further attempts at quantitative interpretation of quenching studies on chromophores attached to biopolymers.