Host‐tumor Antagonism. Xxxiv. The Use of Progestational Agents to Retard Homograft Rejection in Rabbits; A Pilot Study*

Measurement of thymus weight, lumbar node weight and progesterone levels in syngeneically pergnant, allogeneically pregnant, and pseudopergnant mice

“…Some progesterone derivatives increase allograft survival time (Hulka, Mohr & Lieberman, 1965;Peiner & Rhoades, 1965;Turcotte, Haines, Brody, Meyer & Schwarz, 1968) and have been shown to depress delayed type sensitivity (Carter, 1976). More recently progesterone has been shown to suppress P.P.D.-and P.H.A.-induced lymphocyte transformation (Wyle & Kent, 1977).…”

“…The increase in weight has been attri¬ buted to an immunological response to embryonic antigens. However, several studies have shown that corticosteroids and sex steroids can cause lymph node changes (Korenchevsky & Hall, 1938;Persike, 1940b;Pepper, 1961;Peiner & Rhoades, 1965).…”

Host‐tumor Antagonism. Xxxvi. Auto‐immune Disease and Cancer: A Correlation of Data on the Lymphocyte, Thymus, Homograft Rejection and Somatic Mutation*

“…When Pelner and Rhoades (2) first used medroxyprogesterone acetate and hydroxyprogesterone caproate to retard allograft rejection in rabbits, they did not know of Good's work on inhibiting the function of the bursa of Fabricius with a progesterone derivative. We tried progesterone derivatives because the fetus was considered to be a homograft which resisted rejection until the pregnant host was ready to reject it.…”

“…It is well known that the fetus is a homograft, and this form of homograft lives much longer then the usual form. Pelner and Rhoades (2) thought that a possible mechanism was the increase of progestational hormone in the pregnant subject (2). In a pilot experiment with rabbits it was found that injections of medroxyprogesterone acetate and hydroxyprogesterone caproate both cause a delay in homograft rejection ranging from 10–14 days to 40–42 days.…”

“…The homograft or allograft (new terminology) reaction can also be considered as a delayed hypersensitivity reaction, and follows the same laws. The author has successfully used progesterone derivatives (for reasons clarified later) to delay the process of homograft rejection (2).…”