The immunosuppressive effect of burned tissue was studied using a mouse
burn model. To evaluate the immunologic status an in vivo measure of cell-mediated immunity (CMI) involving contact sensitization of mice by painting the skin with
dinitrofluorobenzene was used; mice were challenged 5 days later by painting the ear with the same
antigen. Ear swelling in response to antigenic challenge was used as a quantitative measure of CMI; diminution in ear swelling in treatment mice compared to sensitized, unburned control mice indicated the degree of immunosuppression. A full-thickness
steam burn covering 20% body surface ares (BSA) was profoundly immunosuppressive as reflected by ear swelling of 45 to 60% of that found in normal mice; partial thickness
burns and
burns of 10% BSA extent were not significantly immunosuppressive. Transfer into unburned mice of burned skin equivalent in size to a 20% BSA
burn eschar resulted in marked immunosuppression, but transfer of smaller amounts of burned skin, or of larger amounts of unburned skin and normal and burned liver tissue, did not produce immunosuppression. Mice receiving a very high-temperature (300 degrees C), dry
burn were only slightly more suppressed than mice receiving a standard
steam burn. Normal immunity was preserved in burned mice which received daily application of
cerium nitrate to the
wound for 7 days, but application of other topical agents commonly used in
burn treatment did not preserve immunity. Postburn immunosuppression thus appears related quantitatively to toxic factors in burned skin, and these toxic factors can be abrogated in burned mice by the topical application of
cerium nitrate.