Detection of cell-mediated immunity to sheep erythrocytes by the capillary migration inhibition technique in the lizard, Calotes versicolor

Abstract

Utilizing the in vitro capillary migration inhibition (MI) technique, the cell-mediated immune response to sheep erythrocytes (SRBC) has been studied in the lizard, Calotes versicolor. The viability of spleen cells in culture was above 85%, irrespective of the presence or absence of antigen. Both plaque-forming cell (PFC) and MI responses were found to be antigen-specific. Heat-labile serum factors did not seem to have a role in the MI phenomenon. Both cellular and sonicated membrane preparations of SRBC induced a similar pattern and degree of MI of sensitized spleen cells. Migration of spleen cells was observed within 1 h of the initiation of cultures. The maximum difference between control and experimental cultures occurred by 12 h of incubation. There was an insignificant escape from inhibition after 24 h of culture. Administration of 6× 10⁸ SRBC via the intramuscular route favoured both PFC and MI responses. Although the PFC generation was favoured, only a low level of MI was induced by the intraperitoneal and intracardiac injections. MI and PFC responses are inversely related to the amount of antigen injected. Administration of 10⁴ SRBC resulted in a high degree of MI without the production of PFC. On the other hand, 6×10⁸ SRBC produced an abundant PFC response with a lesser degree of MI. Incorporation of SRBC into Freund's complete adjuvant resulted in the production of MI response with a concurrent reduction in the number of PFC. Formalized SRBC generated a good MI response without the induction of PFC. Sonicated SRBC induced both PFC and MI responses. MI was shown to be mediated by sensitized lymphoid cells. As few as 5% sensitized spleen cells were enough to bring about significant MI of unsensitized spleen cells. Thus, MI has been shown to be an in vitro manifestation of CMI to SRBC in the lizard.