title: [Experimental prevention of a hemolytic disease of the fetus with F (ab)'2 immunoglobulin fragments].
abstract: An experimental study was designed to tentatively protect fetal red blood cells (RBC) against hemolysis by covering fetal RBC antigenic sites with F (ab)'2 fragments of hemolysing antibodies. Sheep antibodies were raised against rabbit RBC. IgG were separated and part of the IgG pool subjected to pepsin digestion, in order to isolate F (ab)'2 fragments. Near term rabbit fetuses were injected through the uterine wall with either IgG, F (ab)'2 or successively F (ab)'2 then IgG. Fetuses were extracted by hysterotomy, one hour after the last injection. Neonatal blood was collected by cardiac puncture for hematocrit determination and detection of hemolysis. Among fetuses injected with IgG alone, nine were deal at hysterotomy and evidenced diffuse hemorrhagic syndrome. Six were born alive with hemolysis, including three with severe anemia. (Ht = 26%). Nine fetuses successively injected with F (ab)'2 and then IgG, were all born alive with normal hematocrits (Ht = 43%). The protective role of F (ab)'2 fragments and their potential therapeutic use are discussed.
mesh_terms: D000818:Animals; D004899:Erythroblastosis, Fetal / Q000517:prevention & control*; D005260:Female; D007140:Immunoglobulin Fab Fragments / Q000008:administration & dosage*; D007074:Immunoglobulin G / Q000276:immunology*; D011247:Pregnancy; D011817:Rabbits
chemical_list: D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G
vernacular_title: Prévention expérimentale d'une maladie hémolytique du foetus par des fragments F (ab)'2 d'immunoglobulines.