Prevention of sexually transmitted HIV infection was investigated in macaques by immunization with a recombinant SIV (simian immunodeficiency virus) envelope gp 120 and core p27 vaccine. In two independent series of experiments, we used the novel targeted iliac lymph node (TILN) route of immunization, aiming close to the iliac lymph nodes draining the genitorectal mucosa. Rectal challenge with the SIVmac 32H J5 molecular clone in two series induced total protection in four out of seven macaques immunized by TILN, compared with infection in 13 of 14 unimmunized macaques or immunized by other routes (P = 0.025). The remaining three macaques showed either a decrease in viral load ( > 90%) or transient viremia, indicating that all seven TILN-immunized macaques showed total or partial protection (P = 0.001). Protection was associated with significant increase in the iliac lymph nodes of IgA antibody-secreting cells to p27 (P < 0.02), CD8-suppressor factor (P < 0.01), and the chemokines RANTES and MIP-1 beta (P < 0.01).

The 70 kDa mycobacterial heat shock protein (Mtb HSP70) stimulates mononuclear cells to release CC-chemokines. We now show that this function of Mtb HSP70, but not human HSP70, is dependent on the cell surface expression of CD40. Deletion of the CD40 cytoplasmic tail abolished, and CD40 antibody inhibited, Mtb HSP70 stimulation of CC-chemokine release. Mtb HSP70 stimulated THP1, KG1 cells, and monocyte-derived dendritic cells to produce RANTES. Specific binding of CD40-transfected HEK 293 cells to Mtb HSP70 was demonstrated by surface plasmon resonance. Coimmunoprecipitation of Mtb HSP70 with CD40 indicates a physical association between these molecules. The results suggest that CD40 is critical in microbial HSP70 binding and stimulation of RANTES production.

The peptide binding C-terminal portion of heat shock protein (HSP)70 (aa 359–610) stimulates human monocytes to produce IL-12, TNF-α, NO, and C-C chemokines. The N-terminal, ATPase portion (HSP701–358) failed to stimulate any of these cytokines or chemokines. Both native and the truncated HSP70359–610 stimulation of chemokine production is mediated by the CD40 costimulatory molecule. Maturation of dendritic cells was induced by stimulation with native HSP70, was not seen with the N-terminal HSP701–358, but was enhanced with HSP70359–610, as demonstrated by up-regulation of CD83, CCR7, CD86, CD80, and HLA class II. In vivo studies in macaques showed that immunization with HSP70359–610 enhances the production of IL-12 and RANTES. Immunization with peptide-bound HSP70359–610 in mice induced higher serum IgG2a and IgG3 Abs than the native HSP70-bound peptide. This study suggests that the C-terminal, peptide-binding portion of HSP70 is responsible for stimulating Th1-polarizing cytokines, C-C chemokines, and an adjuvant function.

The gene spa P (formerly designated as spa Pl) encoding the M, 185,000 surface antigen (I/II) of Streptococcus mutans, serotype c (NGS), has been sequenced. The gene (4683 bp) encodes a protein of 1561 amino acid residues including putative signal peptide (residues I-38) and transmembrane (residues 1537-1556) sequences. The N-terminal region (6(r550) has alanine-rich repeats and is predicted to be a-helical. However, the C-terminal region (800-1540) is proline-rich and favours an extended structure. Except for a short central variable region the sequences appear to be highly conserved for S. mutuns serotype c. N-Terminal sequencing of separated antigen I and antigen II polypeptides suggests that the former represents the N-terminal and the latter the C-terminal portions of the intact antigen.Antigen I/II; Streptococcal surface antigen; spa PI