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HLA Class II‐Like Antiidiotypic Antibodies from Highly Sensitized Patients Inhibit T‐Cell Alloresponses
Author(s) -
Hack N.,
Angra S.,
McKnight T.,
DenHollander N.,
Cardella C. J.
Publication year - 2008
Publication title -
american journal of transplantation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 188
eISSN - 1600-6143
pISSN - 1600-6135
DOI - 10.1111/j.1600-6143.2007.02043.x
Subject(s) - antibody , human leukocyte antigen , medicine , immunology , in vitro , t cell , microbiology and biotechnology , antigen , immune system , biology , biochemistry
The purpose of this study is to identify factors in the sera of highly sensitized (HS) patients (pts) that inhibit T‐cell alloresponses. An in vitro assay was used to measure HLA class I and class II‐like antiidiotypic antibodies (anti‐ids). The stimulation index (SI) was used to measure PBL and T‐cell responses to alloantigens. All HS sera (32 pts) and the IgG fraction inhibited PBL and CD4 + T‐cell responses to alloantigens. The SI with HS IgG was 7.9 ± 1.7 as compared to 31.5 ± 5.9 with normal IgG (p = 0.0003). In a subset of pts who were transiently sensitized, the SI was 6.6 ± 1.0 with a high panel reactive antibody (PRA), but when their PRA was zero, the SI was 17.8 ± 1.3 (p = 0.1). Anti‐ids were found in 100% of 17 pts with a high PRA. The T‐cell inhibitory factors reduced CD4 + T‐cell responses of HS pts to alloantigens in the presence of autologous anti‐ids, were MHC restricted and were inactivated by in vitro generated antibodies to HLA class II‐like anti‐ids. The HLA class II‐like anti‐id IgG molecules bind to the TCR of CD4 + T cells and may impair their ability to help in the downregulating antibody response to anti‐ids.