Abraham G. Osler

In Vitro Studies of Human Ragweed Allergy: Changes in Cellular and Humoral Activity Associated with Specific Desensitization*

Specific hay fever therapy has long been based on the inoculation of pollen extracts, a regimen whose efficacy is not definitely established and whose mode of action is poorly understood (1). At the clinical level, injection of the culpable antigens in subreactive amounts is often followed by symptomatic improvement and diminished allergic responses of the mucous membranes and skin (1-4). Immunologically, these changes coincide with an increased production of blocking and hemagglutinating antibodies and, probably, with a diminution in the skin-sensitizing capacity of the serum (5-8). Despite these findings, efforts to establish a causal relationship between the parenteral injection of antigen, the immune response, and symptomatic relief -have met with considerable difficulty (9, 10). The major problems have been the lack of accurate and valid procedures for assessing the degree of sensitivity to the pollen antigens and for characterizing the patients immune response in terms of his clinical status. Recent reports from this laboratory have outlined in vitro procedures for studying the release

Quantitative Studies of Complement Fixation.

Summary A quantitative method for the determination of complement fixation is briefly described and data are given for its application to one immune system.