“…In vitro tests for CMI, notably lymphocyte trans-formation and cell migration inhibition, have been used to monitor the cellular immune capability of man and animals to various diseases (Kantor, 1975;Rocklin, 1976) including syphilis (Badanoiu et al, 1969;Levene et al, 1969;Janot et al, 1971;Fulford and Brostoff, 1972;Musher et al, 1974;Friedman and Turk, 1975;Musher et al, 1975;Wicher and Wicher, 1975;From et al, 1976;Pavia et al, 1976Pavia et al, , 1977a. In the lymphocyte transformation assay lymphoid cells usually derived from peripheral blood are cultured with a suitable stimulant, especially a mitogen-such as, phytohaemagglutinin (PHA), or concanavalin A (Con A), or a specific test antigen-in this case a treponemal preparation.…”