Investigation of lymph node cell proliferation as a possible immunological correlate of contact sensitizing potential.

In an attempt to define an immunological correlate of contact allergic potential it was investigated whether the magnitude of the lymphocyte proliferative response provoked following primary exposure to skin allergens influences the degree to which sensitization is induced. Previous studies have provided circumstantial evidence that there is a causal relationship between proliferation and sensitization. Thus, inhibition of the primary proliferative response to a sensitizing chemical, induced by prior exposure to an unrelated allergen, is associated with a significant depression of contact hypersensitivity. The results of comparative studies performed using a series of antigenically cross-reactive dinitrobenzene derivatives, 2,4-dinitrofluorobenzene, 2,4-dinitrochlorobenzene and 2,4-dinitrothiocyanobenzene are now reported. Evidence is presented that there is a direct correlation between cumulative proliferative activity in the draining lymph nodes and the severity of elicitation reactions. The tentative conclusion which can be drawn is that measurement of lymphocyte proliferative activity may form the basis of a method for comparative evaluation of the contact allergic potential of chemicals.