Monoclonal antibodies to mammalian heat shock proteins impair mouse embryo development in vitro

Two-cell mouse embryos (B6D2F1) were cultured in the presence or absence of100 microg/ml monoclonal antibodies specific for the mammalian 60 kDa(HSP60), 70 kDa (HSP70) and 90 kDa (HSP90) heat shock proteins. Embryodevelopment was evaluated after 3, 5 and 7 days in culture by determiningthe number of blastocysts, hatched blastocysts and outgrown trophoblasts atthe successive time points. At day 3, only 29% (22/75) of the embryoscultured with anti-HSP60 antibody developed to the blastocyst stage (P <0.0001) as compared to 67% (31/46) of the embryos cultured with anti-HSP70,72% (43/60) cultured with anti-HSP90, and 79% (49/62) in medium plus mouseIgG1. By day 5, hatched embryos were present in 28% (13/ 46) of thecultures containing anti-HSP70 (P < 0.0001), as opposed to 57% (34/60)containing anti-HSP90 and 73% (45/62) containing IgG1. At day 7, outgrowntrophoblasts were observed in 9% (4/46) of cultures containing anti-HSP70(P < 0.0001), 45% (27/60) containing anti-HSP90 (P < 0.01) and 66%(41/62) cultured in medium plus IgG1. Antibodies to different heat shockproteins exerted a detrimental effect on mouse embryo development at uniquedevelopment stages. Immune sensitization to heat shock proteins may be acause of reproductive failure.