The major objectives of this proposal are to clarify the molecular basis for, and the significance and generality of, Fc region-dependent, cooperative binding of antibodies to antigen. In addition, we will characterize IgG subclass-associated difference in other functional properties. The experimental approaches to be employed are delineated below. First, the functional affinities of IgG antibodies expressing different heavy chain constant domains will be compared with respect to different (particularly with regard to epitope spacing) forms of antigen under a variety of conditions (e.g., temperature or ionic strength). Monoclonal antibodies (mAbs) of different IgG subclasses, but expressing identical, or comparable, variable domains will be used for these studies. Second, the sites in the gamma 3 Fc region that are involved in cooperative binding will be mapped by serologic and electron microscopic methods. Third, the murine IgG subclasses will be compared with respect to clearance and protection in a murine model infection with Streptococcus pneumoniae. Forth, mAbs with novel binding phenotypes will be selected and characterized, and new strategies for endowing antibodies with the ability to bind cooperatively will be evaluated. These studies should contribute to an understanding of the functional differences among IgG subclasses, particularly in the contexts of anti- bacterial and anti-polysaccharide antibody responses. Further more, by increasing our understanding of the relationships between antibody constant domain structure and function, these studies should suggest novel ways to alter antibody structure to enhance desired functional properties.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
Application #
Study Section
Allergy and Immunology Study Section (ALY)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Case Western Reserve University
Schools of Medicine
United States
Zip Code
Greenspan, N S; Cooper, L J (1995) Complementarity, specificity and the nature of epitopes and paratopes in multivalent interactions. Immunol Today 16:226-30
Ubol, S; Levine, B; Lee, S H et al. (1995) Roles of immunoglobulin valency and the heavy-chain constant domain in antibody-mediated downregulation of Sindbis virus replication in persistently infected neurons. J Virol 69:1990-3
Cooper, L J; Robertson, D; Granzow, R et al. (1994) Variable domain-identical antibodies exhibit IgG subclass-related differences in affinity and kinetic constants as determined by surface plasmon resonance. Mol Immunol 31:577-84
Greenspan, N S; Cooper, L J (1993) Cooperative binding by mouse IgG3 antibodies: implications for functional affinity, effector function, and isotype restriction. Springer Semin Immunopathol 15:275-91
Schreiber, J R; Cooper, L J; Diehn, S et al. (1993) Variable region-identical monoclonal antibodies of different IgG subclass directed to Pseudomonas aeruginosa lipopolysaccharide O-specific side chain function differently. J Infect Dis 167:221-6
Cooper, L J; Shikhman, A R; Glass, D D et al. (1993) Role of heavy chain constant domains in antibody-antigen interaction. Apparent specificity differences among streptococcal IgG antibodies expressing identical variable domains. J Immunol 150:2231-42
Greenspan, N S; Cooper, L J (1992) Intermolecular cooperativity: a clue to why mice have IgG3? Immunol Today 13:164-8
Cooper, L J; Schimenti, J C; Glass, D D et al. (1991) H chain C domains influence the strength of binding of IgG for streptococcal group A carbohydrate. J Immunol 146:2659-63
Turner, J R; Tartakoff, A M; Greenspan, N S (1990) Cytologic assessment of nuclear and cytoplasmic O-linked N-acetylglucosamine distribution by using anti-streptococcal monoclonal antibodies. Proc Natl Acad Sci U S A 87:5608-12