Detection of soluble class I molecules (non HLA-A or HLA-B) in serum, spleen membranes and lymphocytes in culture.
Soluble major histocompatibility complex class I molecules (sHLA) present in human serum can be resolved by gel filtration into two different peaks with an apparent molecular mass of about 200 kDa (30% of the total) and 50-60 kDa (60%-70%). The serological analysis of the peaks shows that A or B specificities can only be detected in the 200 kDa peak while both are recognized by the monomorphic W6/32 monoclonal antibody (mAb) and anti-beta 2-microglobulin mAb. Such sHLA (non HLA-A or -B) molecules are released from human spleen membranes upon incubation at 37 degrees C and have been purified by affinity chromatography with mAb W6/32 bound to Sepharose. The molecular mass analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the sHLA (non HLA-A or -B) and of the classical HLA-A or -B antigens still bound to the membranes and purified from the same membranes after detergent solubilization does not show a significant difference, indicating that sHLA do not represent proteolytic fragments of the classical HLA-A or -B antigens. The presence of sHLA (non HLA-A or -B) has also been detected in the supernatants of lymphocyte cultures and increases dramatically upon stimulation by mitogens. The effect of pokeweed mitogen, phytohemagglutinin, Staphylococcus aureus Cowan strain and phorbol 12-myristate 13-acetate on the secretion of sHLA has been studied. The molecular mass of the secreted sHLA (detected using [14C]leucine) is compared with the classical transmembrane proteins.
Villar
L M
LM
Servicio de Inmunología, Hospital Ramón y Cajal, Madrid, Spain.
Roy
G
G
Lázaro
I
I
Alvarez-Cermeno
J C
JC
González
M
M
Brieva
J A
JA
Del la Sen
M L
ML
Leoro
G
G
Bootello
A
A
González-Porqué
P
P
D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D015234:HLA-A Antigens / Q000032:analysis*; D015235:HLA-B Antigens / Q000032:analysis*; D006801:Humans; D008214:Lymphocytes / Q000276:immunology*; D008970:Molecular Weight; D013154:Spleen / Q000276:immunology*
D002614:Chelating Agents; D015234:HLA-A Antigens; D015235:HLA-B Antigens