The work embodied in this paper deals with serological effects produced in rabbits by injections of ragweed pollen extracts, and the relation of immune anti-sheep hemolysins to the homologous antigen, the Forssman antigen, and finally h u m a n erythrocytes of groups A and B.The second p a r t of the work deals with the effect of ragweed pollen injections on the hemolysin titre of patients sensitive to ragweed (hay fever).
MethodsHeterophile phenomena observed by Forssman (1), Ehrlich and others (2), challenged the theory of the specificity of serological reactions. Closer investigation by Landsteiner (3), revealed that heterophile phenomena in zoologically unrelated forms probably denote the presence of chemically similar groups. These are now recognized as non-protein haptens, and are responsible for a rather broad specificity. Heterophile antigens are found in the organs and blood of animals of various species as well as in bacteria and plants (2). There are varieties of heterophile antibodies other than the Forssman type (4). Not all heterophile antigens reproduce the classical experiment of Forssman. Schiff and Adelsberger noted the immunological relationship between heterophile tissue antigens and isoagglutinogens of human blood groups A and AB. Forssman antisera react with cells of these two groups, but not with groups O or B. Most sera specific for A red blood cells, hemolyze the cells of the sheep.Gay (5) states that although first shown by Schiff and Adelsberger (6), to be alcoholsoluble, alcohol-insoluble but water-soluble preparations were obtained from human secretions and excretions (Brahn and Schiff). Human urine and commercial pepsin, both of which contain a factor similar to the human A hemagglutinogen, revealed the presence of a reactive substance, which yielded sugar upon hydrolysis (Brahn, Schiff, and Weinmann, Freudenberg et al.). Landsteiner (7), studied the "A" factor in horse saliva and described the largest part of the refined product as carbohydrate in nature. Certain gums, namely gum acacia (8), cherry gum (9), mesquite gum (10), and flaxseed mucilage (11), contain chemical groups, similar to "A" substance.Garvin and Kurland (12) did not observe an increase in titre of Forssman heterophile antibody in human or rabbit sera, following treatment with ragweed pollen. Sinclair and Thomas (13a), who studied the heterophile titre in the sera of 148 consecutive allergic patients, treated and untreated, concluded that in the allergic group the patients 591
