INVESTIGADORES
ROGUIN Leonor Patricia
artículos
Título:
Properties of cryptic epitopes and their corresponding antibodies as indicated by the study of human and ovine growth hormones
Autor/es:
LOUREIRO M.E.; MARINO, V. J; MATHIEU, P:A; DUHALDE M; ROGUIN, L.P.; PEÑA, C; RETEGUI, L.A
Revista:
IMMUNOLOGICAL INVESTIGATIONS
Editorial:
Informa Healthcare
Referencias:
Lugar: London, UK. ; Año: 2007 vol. 36 p. 159 - 174
ISSN:
0882-0139
Resumen:
Antibodies (Ab) directed to hidden antigenic determinants (cryptotopes) are undesirable
because they are not neutralizing. Additionally, we have previously demonstrated
a close association between the extent of Ab to cryptic determinants and the expression
of autoantibodies (autoAb) under some experimental conditions. Thus, the first objective
of this work was to establish the physicochemical characteristics of Ab to cryptotopes
and the second one was to examine the structural features of cryptic epitopes
themselves. Using human and ovine growth hormones (hGH and oGH) as antigenic
models and competition ELISA under different conditions of temperature, pH or ionic
strength, we did not find any difference between the binding properties of anti-cryptic
epitope antibodies (Ab) and anti-native epitope Ab. Then, using synthetic peptides and
tryptic digests and direct and competition ELISAs we studied the structures of cryptic
hGH and oGH epitopes. Isolated peptides either in solution or adsorbed on microplates
failed to react. Partially digested hGH was recognized only when insolubilized on
microplates, and anti-oGH Ab only reacted with a large fragment of the hormone either
in solution or insolubilized. These results indicate that, at least in the case of hGH and
oGH, cryptic epitopes are not simple linear sequences, as commonly referred without
any evidence, but new exposed conformational structures different from those found in
the native antigen.