Stimulatory effect of Vibrio cholerae neuraminidase on the antibody response to various antigens

Vibrio cholerae neuraminidase (VCN) splits off peripheral sialic acids from cell membranes. Treatment of tumour cells with VCN increases their immunogenicity and it has been suggested that VCN may unmask hidden tumour specific antigens. On the other hand, it has been shown that VCN can affect the cell-cell interactions of immune cells in vitro and it seems possible that the enzyme may have a direct effect on the immune response to antigen in vivo.

The present report describes the effect of VCN on the antibody response of mice to SRBC, to antigens which do not contain peripheral neuraminic acid such as certain bacterial vaccines and rubella virus, and to the soluble antigen BSA.

VCN injected i.m. or i.p., but not i.v., together with the antigens increases; (1) the PFC response to SRBC, (2) the antibody response to various bacteria (E. coli, V. cholerae, S. typhimurium), (3) the antibody response to rubella virus, and inhibits tolerance induction by aggregate free BSA.

The optimal dose required to stimulate the antibody response is between 0.5 and 50 units per animal. Possible mechanisms of the adjuvant activity of VCN are discussed.