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Infect. Immun., Jun 1997, 2197-2205, Vol 65, No. 6
M El-Demellawy, R El-Ridi, NI Guirguis, M Abdel Alim, A Kotby and M Kotb
Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) are
autoimmune sequelae of upper respiratory infections with group A
streptococci (GAS). To gain a better understanding of the pathogenesis of
these diseases, we examined the in vitro proliferative responses of
peripheral blood mononuclear cells (PBMC) from RHD patients to human
myocardial proteins in a T-cell Western assay. A number of myocardial
proteins fractionated by sodium dodecyl sulfate-polyacrylamide gel
electrophoresis were recognized by PBMC from both patients and controls.
However, PBMC from a significant percentage of RHD patients (40%) responded
to a discrete band of myocardial proteins migrating with an apparent
molecular mass of 50 to 54 kDa while none of the control subject PBMC
responded to this protein band (P < or = 0.0001). To further investigate
the link between infections with GAS and autoimmune carditis, we studied
the proliferative responses of PBMC from patients and controls to
myocardial proteins before and after in vitro stimulation of the cells with
opsonized GAS isolated from ARF patients. Priming of PBMC with
rheumatogenic GAS caused the percentage of RHD patients responding to the
50- to 54-kDa myocardial proteins to increase from 43 to 90% (P < or =
0.0284). By contrast, PBMC from control subjects failed to recognize the
50- to 54-kDa myocardial proteins even after stimulation with the opsonized
streptococci (P < or = 0.0001). The assay sensitivity was increased from
40 to 90% after priming of a patient's cells with opsonized GAS, but the
positive predictive value was 100% in both unprimed and primed cultures.
Antibodies generated to partially purified 50- to 54-kDa myocardial
proteins did not cross-react with either streptococcal homogenates,
purified M protein, myosin, laminin, or vimentin, suggesting a lack of
cross-reactivity at the humoral level. This study suggests that the 50- to
54-kDa myocardial proteins contain a putative antigen that is
preferentially recognized by T cells from RHD patients and demonstrates
that exposure to streptococcal antigens enhances the ability of patients to
recognize these proteins.
Copyright © 1997, American Society for Microbiology
Preferential recognition of human myocardial antigens by T lymphocytes from rheumatic heart disease patients
Veterans Affairs Medical Center and Department of Surgery, The University of Tennessee, Memphis 38104, USA.
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