Murine Rous-sarcoma-specific immunity detected by leukocyte adherence inhibition: inhibitory effect of normal serum.

The standard one-stage lymphocyte adherence inhibition (LAI) assay was used to investigate cellular and humoral immune responses within the murine Rous sarcoma system. Significant specific cellular reactivity to Rous sarcoma antigen extracts was detected when the responder peritoneal exudate cells (PEC) were obtained from mice bearing or immunized against primary or transplanted Rous sarcomas; no cellular reactivity to control methylcholanthrene (MC)-induced tumor antigen extracts was observed. Similarly, specific cell-mediated recognition of MC tumor antigen extract was demonstrated. Initial experiments designed to assess the role of serum components in the LAI assay demonstrated that normal mouse serum of C57BL/10ScSn, B10.D2, or A/WySn origin, either fresh or frozen, obtained from old (over 7 months) or young (under 6 weeks) mice non-specifically abrogated the specific loss of PEC adherence.