Ian A. York wrote:
> ... at this point my main
> question is whether Hela are homozygous at HLA-B, because I want to be
> able to say that there are 6 HLA molecules in them. It will become more
> important later on.
>> I'm pretty sure our Hela are not HLA-A3, because they stain negative with
> GAP-A3 while transfected HLA-A0302 stains positive in them.
>
I thought our staining results might be of interest:
HeLa stain with the 4D12 antibody, which recognizes a "HLA determinant
that includes specificities within, but not identical to, the B5
cross-reactive group" (ATCC)[MS under revision].
They are negative for HLA-A2 and -B8 using antibodies BB7.2 or MA2.1 and
0201HA or 0402HA (One Lambda), though they can express transfected heavy
chain genes encoding these molecules [Johnson and Mook-Kanamori J. Biol.
Chem 275: 16643 (2000)].
> I wonder if the disagreement in typing is because of different methods,
> problems with the methods, or because various people have different cells
> they call "HeLa" because of cross-contaimination.
>> Ian
True, different methods as well as the extreme aneuploidy of HeLa
probably contribute to the disagreement. The total chromosome count -
and the numbers of each chromosome - among HeLa cell lines can vary
tremendously. The old ATCC catalog had great documentation of this but I
can't find it in their on-line catalog. With all that, it's amazing how
uniform the expression of HLA is on the surface of HeLa cells - very
consistent, essentially gaussian distributions - although that may be a
consequence of single clones dominating the culture.
Do you want to know whether there are 6 genes or 6 transcripts? Of
course, the expression of one or more alleles might have been
extinguished, so that the genetic typing could yield a (diploid)
heterozygote but the serological or mRNA typing would yield a homozygote.
Best of luck.
--
David R. Johnson, Ph.D.
Research Scientist, Department of Pathology
454 BCMM, 295 Congress Avenue
Yale University School of Medicine, New Haven, CT 06510 USA
Tel.: 203/737-2298, Fax: 203/737-2293
http://johnsond3.med.yale.edu
