A letter after HLA, such as HLA-D, refers to a gene l____s.
Class I antigens are coded for by the HLA-_, _, and _ genes. Each gene is highly
pleomorphic, which means it occurs in various distinct f___s. The A gene is
currently recognized to have at least 23 s____ties, the B gene 50 s_________s,
and the C gene 8 s_____s. HLA-A, B, and C antigens are found on virtually
e____y human cell.
Class II antigens are different s_____ly and f_____ly from Class I. The exact
number of g__s in the D region is uncertain but three are widely accepted. These
are DR, DP, and DQ. HLA-DR, DP, and DQ are found chiefly on the s____e of
immunocompetent cells, including m____ge/monocytes, r___ing T lymphocytes,
a____ted T lymphocytes, and particularly B l_____s.
Class III genes are the structural genes for p___ns C2, C4A, C4B, and factor B of
the c____t system.
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