HISTOPHYSIOLOGY OF LYMPHOCYTE-TISSUE COMPLEXES IN HUMAN FETAL INTESTINE

Using histochemical and immunological methods, the development of lymphocyte-tissue complexes in the distal part of human fetal intestine (appendix, Peyer's patch) was studied in relation to the changes taking place in the ileocecal lymph nodes. It was found that this autonomous gut immune system started to function in the second trimester of fetal development. It is dominated by T-cell system of the immunity. After the appearance of meconium in the intestinal lumen, the phenotypical diversity of lymphocytes within the organ was increased, but it did not reach the level found in mature organism. The ileocecal lymph nodes are distinguished by their lymphocyte composition as a T-cell depot in this interorgan and intertissue system, which provides essential homeostasis of the developing fetus.

human fetus, appendix, Peyer's patch, ileocecal lymph nodes