[Morphological studies in delayed hypersensitivity to streptococcal antigens using film preparations of the...

Film preparations of the mesentery were used for morphological study of cell reactions, connected with the delayed type hypersensitivity (DTH). Twenty-four hours after intraperitoneal injection of small doses of the streptococcal thermostable fraction (TST fraction) the guinea-pigs sensitized with streptococcal culture developed a more intensive, as compared with control animals, diffuse infiltration of the peritoneum with mixed type cells (lymphocytes, monocytes and polynuclear leukocytes) abundant in mononuclear elements. With TST fraction dose build up the infiltration demonstrated an abrupt increase in polynuclear leukocytes completely masking the monocytic reaction in some cases. Large aggregations of lymphocytes were seen in the prelymph sinuses accompanying blood capillaries and nervous stemlets. Detection in the peritoneum of cell reactions characteristic of DTH following the injection of certain doses of specific antigens and comparative simplicity of obtaining film preparations allow recommending the technique described for disclosing and experimental study of DTH to microbial antigens.