Effects of anti-idiotype vaccine on tumour growth and on production of soluble factors modulating cell-mediated immunity in vitro.

The previous observation, that single i.p. doses of a monoclonal anti-idiotypic antibody (MAIA) injected into BALB/c mice induced suppressor factors, was extended to multiple i.v. doses. These induced enhancing factors, which were produced in spleen cell cultures, required L3T4+ cells for their formation, lacked the IJ marker, and bound to anti-immunoglobulin, showing them to be antibodies. Selective immunoabsorption demonstrated two separate enhancing antibodies; both bound to MAIA but they had different affinities for specific and non-specific tumour antigens. Subsequently, single and multiple MAIA doses were tested in vivo for their effects on tumour growth. The single doses had variable effects depending on time of administration, and these effects were tumour-specific; the multiple doses strongly inhibited tumour growth when given before tumour challenge, but also had non-specific effects on another tumour as anticipated from the in vitro results.