Effect of Ultraviolet Light on Dinitrochlorobenzenespecific Antigen-Presenting Function

HLA-A and -B antigens are resistant to ultraviolet (UV) light whereas HLA-D, as defined by the mixed leukocyte culture reaction (MLR), is sensitive to UV light in initial or first culture. In primed LD typing, the HLA-D responsible for stimulation is relatively resistant to UV light in second culture. We have developed a method for evaluating a specific proliferative response to DNP in dinitrochlorobenzene (DNCB)-sensitized human subjects and found a requirement for a component of autologous leukocytes to activate DNP-responsive lymphocyte clones. Autologous DNBSO₃-coupled leukocytes with and without UV were used to stimulate lymphocytes in DNCB-sensitized subjects. ³HTdR incorporation was measured after 4 or 5 dys in 1st or “primary” culture. After 9 to 14 days, blast-derived lymphocytes were set up in 2nd or “secondary” cultures and exposed to the same autologous DNBSO₃-treated leukocytes with and without UV. Accelerated ³HTdR incorporation was measured in these secondary clonally primed cultures after 20 to 44 hr. The results showed that UV light abrogated the antigen-presenting or stimulator function in the 1st culture and diminished, but did not abrogate, the antigen-presenter function in the 2nd culture. These findings indicate that the DNP-antigen presenting function is behaving in a manner similar to that observed for mixed leukocyte culture determinants in 1st and 2nd cultures.