Production of foetally stimulated lymphocytotoxic antibodies by multiparous cows

Abstract

Summary Serum samples were collected monthly from second gestation cows and examined for the presence of lymphocytotoxic antibodies. Of 25 cows studied 16 (64 %) raised antibodies during or immediately after second gestation. Ten of these cows (40 %) raised antibodies during gestation, some as early as 5 months before parturition. Reactors which had had first‐gestation reactivity responded earlier, but had peak antibody titers no higher than cows without observable first gestation reactions. Cows with antibodies of similar specificity in the first two gestations responded earlier than those with different antibody specificities. Regardless of the time of first antibody detrection, peak titers were usually achieved during the first month postpartum. Antibody persistence increased with parity. Among cows of all ages sampled at random times, there was a linear relationship of serum reactivity to cow age.

Haematopoietic depletion in vaccine-induced neonatal pancytopenia depends on both the titre and specificity of alloantibody and levels of MHC I expression

“…An alteration in BNP-dam alloantibody specificity might be expected at subsequent parturitions, if BNP-alloantibody was being stimulated by exposure to foetal MHC I alleles, as naturally occurring alloantibody has broader specificity in multiparous than primiparous cows, [16]. As this is not the case, it appears the foetus does not directly influence the specificity of BNP-alloantibody.…”

“…However, the specificity of these alloantibodies for individual MHC I alleles, or quantitative analysis of their functional activity, has not been previously demonstrated. Furthermore it has been suggested that Pregsure might also boost normal pregnancy-induced alloantibodies against paternally-derived MHC antigens [6], which have been detected previously in the sera of healthy cows [15,16].…”

“…However, previous attempts at inducing complementmediated lysis by binding of BNP-alloantibody have been reported to be unsuccessful [17]. Complement-dependent cytotoxicity (CDC) assays are routinely used in pre-transplant screening of recipients for MHC I alloantibody, as this method is considered to give clinically relevant results [18,19] and CDC assays have also been used in cattle to detect naturally-occurring pregnancy-induced serum alloantibodies [16,20].…”

The role of placental MHC class I expression in immune-assisted separation of the fetal membranes in cattle

“…The production of fetal alloantigen specific IgG antibodies, which can be detected during pregnancy (Hines and Newman, 1981), depends on self MHC II restricted CD4 T cell help and shows that the indirect pathway of allorecognition indeed occurs during pregnancy.…”

“…Preventing immunological rejection of the fetus is, therefore, critical for a successful pregnancy. Maternal antibodies against paternal alloantigens are induced in up to 64% of multiparous cattle and can be detected as early as the second trimester of gestation (Hines and Newman, 1981), showing that the materno-fetal immune response is regulated, rather than suppressed, and is normally not harmful to the fetus. In cattle, delayed expulsion of the fetal membranes, a common reproductive disorder, is associated with a reduced maternal (allo)immune response (Benedictus et al, 2011;Benedictus et al, 2012;Gunnink, 1984b;Joosten et al, 1991), suggesting that at parturition a materno-fetal alloimmune response may be beneficial for the separation of the fetal membranes.…”