Previous Article | Next Article ![]()
J. Virol., 01 1998, 460-466, Vol 72, No. 1
TL Chapman and PJ Bjorkman
Both human and murine cytomegaloviruses (HCMV and MCMV) down-regulate
expression of conventional class I major histocompatibility complex (MHC)
molecules at the surfaces of infected cells. This allows the infected cells
to evade recognition by cytotoxic T cells but leaves them susceptible to
natural killer cells, which lyse cells that lack class I molecules. Both
HCMV and MCMV encode class I MHC heavy-chain homologs that may function in
immune response evasion. We previously showed that a soluble form of the
HCMV class I homolog (U(L)18) expressed in Chinese hamster ovary cells
binds the class I MHC light- chain beta2-microglobulin and a mixture of
endogenous peptides (M. L. Fahnestock, J. L. Johnson, R. M. R. Feldman, J.
M. Neveu, W. S. Lane, and P. J. Bjorkman, Immunity 3:583-590, 1995).
Consistent with this observation, sequence comparisons suggest that U(L)18
contains the well- characterized groove that serves as the binding site in
MHC molecules for peptides derived from endogenous and foreign proteins. By
contrast, the MCMV homolog (m144) contains a substantial deletion within
the counterpart of its alpha2 domain and might not be expected to contain a
groove capable of binding peptides. We have now expressed a soluble version
of m144 and verified that it forms a heavy chain-beta2- microglobulin
complex. By contrast to U(L)18 and classical class I MHC molecules, m144
does not associate with endogenous peptides yet is thermally stable. These
results suggest that U(L)18 and m144 differ structurally and might
therefore serve different functions for their respective viruses.
Copyright © 1998, American Society for Microbiology
Characterization of a murine cytomegalovirus class I major histocompatibility complex (MHC) homolog: comparison to MHC molecules and to the human cytomegalovirus MHC homolog
Division of Biology, California Institute of Technology, Pasadena 91125, USA.
This article has been cited by other articles:
Copyright © 2010 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»