The analysis with monoclonal antibodies of the heterogeneity of Ia glycoproteins on chronic lymphocytic leukemia cells

Journal Article · Mon Nov 01 00:00:00 EST 1982 · J. Immunol.; (United States)

OSTI ID:5686032

Addis, J B ^[1]; Tisch, R; Falk, J A; Letarte, M

---

1. Hospital for Sick Children, Toronto, Canada

The accessible Ia molecules on the surface of chronic lymphocytic leukemia (CLL) cells were quantitated in the cellular radioimmunoassay with saturating concentrations of monoclonal antibodies. Monoclonal antibody 21w4, like DA/2 antibody, recognizes monomorphic determinants of human Ia antigens.The amount of 21w4 or DA/2 bound to CLL cells derived from eight patients (varying from 2.6 to 13.9 x 10/sup 5/ molecules/cell) appears to be the maximum observed with the antibodies studied. Two other antibodies, 18d5 and 21r5, although also directed at nonpolymorphic Ia determinants, bind differentially to CLL cells, with the ratios of 21r5/21w4 and 18d5/21w4 varying from 0.08 to 0.90. Sequential immunoprecipitation studies have established that the four epitopes 18d5, 21r5, 21w4, and DA/2 were present on the same molecules. All Ia molecules express 21w4 and DA/2 epitopes, whereas only certain subsets of Ia molecules carry accessible 21r5 or 18d5 epitopes. Competitive binding studies showed that the epitopes recognized by the four monoclonal antibodies were different. Monoclonal antibodies 21r5 and 21w4 did not inhibit each other's binding. Furthermore, binding of 21w4 to CLL cells potentiated the binding of /sup 125/I-21r5 IgG to the same cells, suggesting that binding of 21w4 antibody induces a conformational change in the molecule that renders 21r5 epitopes more accessible.

• OSTI ID: 5686032
• Journal Information: J. Immunol.; (United States), Vol. 129:5
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
GLUCOPROTEINS
RADIOIMMUNOASSAY
BLOOD CELLS
IMMUNOLOGY
IODINE 125
LEUKEMIA
LYMPHATIC SYSTEM
MONOCLONAL ANTIBODIES
PATIENTS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BODY FLUIDS
CARBOHYDRATES
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
HEMIC DISEASES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MATERIALS
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOASSAY
RADIOISOTOPES
SACCHARIDES
TRACER TECHNIQUES
550601* - Medicine- Unsealed Radionuclides in Diagnostics