Skip to main content
PMC home page
Clinical and Experimental Immunology logoLink to Clinical and Experimental Immunology
. 1997 Nov;110(2):310–316. doi: 10.1111/j.1365-2249.1997.tb08333.x

Quantitative analysis of C4Ab and C4Bb binding to the C3b/C4b receptor (CR1, CD35)

B D REILLY *, C MOLD *
PMCID: PMC2265500  PMID: 9367418

Abstract

Complement-dependent clearance of immune complexes in humans is dependent on the activation and binding of the early components of the classical complement cascade. This prevents immune complex precipitation and promotes binding of the complexes by the C4b/C3b complement receptor CR1 (CD35) found on erythrocytes. The fourth component of human complement is encoded by two closely linked genes within the MHC. These genes give rise to the isotypic forms C4A and C4B, and recent studies suggest that CR1 binds activated C4A (C4Ab) to a greater extent than activated C4B (C4Bb). To study this difference in a more quantitative way the binding reactions between CR1 and C4Ab- and C4Bb-coated immune complexes and between CR1 and soluble dimers of C4Ab (C4Ab2) and C4Bb (C4Bb2) were analysed using the native receptor on human erythrocytes. The binding reaction between immune complexes with equivalent amounts of covalently bound C4Ab or C4Bb and erythrocyte CR1 showed a two-fold higher binding of complexes coated with C4A. Furthermore, erythrocyte CR1 bound C4Ab2 with an apparent four-fold higher affinity (Kd ≍ 1.4 10−7M) than C4Bb2 (Kd ≍ 4–8 10−7M), indicating a preferential binding of CR1 for C4A.

Keywords: lupus, complement, autoimmunity, complement receptors

Full Text

The Full Text of this article is available as a PDF (903.9 KB).

References

  • 1.Tack BF. The beta-Cys-gamma-Glu Molester bond in human C3 and C4. Springer Semin Immunopathol. 1983;6:259. doi: 10.1007/BF02116276. [DOI] [PubMed] [Google Scholar]
  • 2.Law SK, Lichtenberg NA, Levine RP. Covalent binding and hemolytic activity of complement proteins. Proc Natl Acad Sci USA. 1980;77:7194. doi: 10.1073/pnas.77.12.7194. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Naama JK, Mitchell WS, Zoma A, et al. Complement-mediated inhibition of immune precipitation in patients with immune complex diseases. Clin Exp Immunol. 1983;51:292. [PMC free article] [PubMed] [Google Scholar]
  • 4.Schifferli JA, Ng YC, Peters DK. The role of complement and its receptor in the elimination of immune complexes. N Engl J Med. 1986;21:488. doi: 10.1056/NEJM198608213150805. [DOI] [PubMed] [Google Scholar]
  • 5.Schifferli J A, Ng YC, Estreicher J, et al. The clearance of tetanus toxoid/ anti-tetanus toxoid immune complexes from the circulation of humans. Complement- and erythrocyte complement receptor 1-dependent mechanisms. J Immunol. 1988;140:899. [PubMed] [Google Scholar]
  • 6.Comacoff JB, Hebert LA, Smead WL, et al. Primate erythrocyte-immune complex-clearing mechanism. J Clin Invest. 1983;71:236. doi: 10.1172/JCI110764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Hauptmann G, Goetz J, Uring-Lambert B, et al. The fourth component. Prog Immunol. 1986;39:232. [PubMed] [Google Scholar]
  • 8.Hauptmann G, Tappeiner G, Schifferli JA. Inherited deficiency of the fourth component of human complement. Immunodefic Rev. 1988;1:3. [PubMed] [Google Scholar]
  • 9.Belt KT, Carroll MC, Porter RR. The structural basis of the multiple forms of human complement component C4. Cell. 1984;36:907. doi: 10.1016/0092-8674(84)90040-0. [DOI] [PubMed] [Google Scholar]
  • 10.Belt KT, Yu CY, Carroll MC, et al. Polymorphism of human complement component C4. Immunogenetics. 1985;21:173. doi: 10.1007/BF00364869. [DOI] [PubMed] [Google Scholar]
  • 11.Porter RR. Complement polymorphism, the major histocompatibility complex and associated disease: a speculation. Molec Biol Med. 1983;1:167. [PubMed] [Google Scholar]
  • 12.Fielder AHL, Walport MJ, Batchelor JR, et al. Family study of the major histocompatibility complex in patients with systemic lupus erythematosus: importance of null alleles of C4A and C4B in determining disease susceptibility. Br Med J. 1983;286:425. doi: 10.1136/bmj.286.6363.425. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Kemp ME, Atkinson JP, Skanes VM, et al. Deletion of C4A genes in patients with systemic lupus erythematosus. Arthritis Rheum. 1987;30:1015. doi: 10.1002/art.1780300908. [DOI] [PubMed] [Google Scholar]
  • 14.Briggs DC, Senaldi G, Isenberg DA, et al. Influence of C4 null alleles on C4 activation in systemic lupus erythematosus. Ann Rheum Dis. 1991;50:251. doi: 10.1136/ard.50.4.251. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Howard PF, Hochberg MC, Bias WB, et al. Relationship between C4 null genes, HLA-D region antigens, and genetic susceptibility to systemic lupus erythematosus in Caucasian and black Americans. Am J Med. 1986;81:187. doi: 10.1016/0002-9343(86)90250-0. [DOI] [PubMed] [Google Scholar]
  • 16.Fielder AHL, Walport MJ, Batchelor JR, et al. Family study of the major histocompatibility complex in patients with systemic lupus erythematosus: importance of null alleles of C4A and C4B in determining disease susceptibility. Br Med J. 1983;286:425. doi: 10.1136/bmj.286.6363.425. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Batchelor JR, Fielder AHL, Walport MJ, et al. Family study of major histocompatibility complex in HLA DR3 negative patients with systemic lupus erythematosus. Clin Exp Immunol. 1987;70:364. [PMC free article] [PubMed] [Google Scholar]
  • 18.Law SKA, Dodds AW, Porter RR. A comparison of the properties of two classes, C4A and C4B, of the human complement component C4. EMBOJ. 1984;3:1819. doi: 10.1002/j.1460-2075.1984.tb02052.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Isenman DE, Young JR. The molecular basis for the difference in immune hemolysis activity of the chido and rodgers isotypes of human complement component C4. J Immunol. 1984;133:3019. [PubMed] [Google Scholar]
  • 20.Carroll MC, Fathallah DM, Bergamaschini L, et al. Substitution of a single amino acid (aspartic acid for histidine) converts the functional activity of human complement C4B to C4A. Proc Natl Acad Sci USA. 1990;87:6868. doi: 10.1073/pnas.87.17.6868. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Paul L, Skanes VM, Mayden J, et al. C4-mediated inhibition of immune precipitation and differences in inhibitory action of genetic variants, C4A3 and C4B1. Complement. 1988;5:110. doi: 10.1159/000463045. [DOI] [PubMed] [Google Scholar]
  • 22.Kishore N, Shah D, Skanes VM, et al. The fluid-phase binding of human C4 and its genetic variants, C4A3 and C4B1, to immunoglobulins. Mol Immunol. 1988;25:811. doi: 10.1016/0161-5890(88)90117-4. [DOI] [PubMed] [Google Scholar]
  • 23.Schifferli JA, Hauptmann G, Paccaud JP. Complement-mediated adherence of immune complexes to human erythrocytes. FEBS Letters. 1987;213:415. doi: 10.1016/0014-5793(87)81533-8. [DOI] [PubMed] [Google Scholar]
  • 24.Gatenby PA, Barbosa JE, Lachmann PJ. Differences between C4A and C4B in the handling of immune complexes: the enhancement of CR1 binding is more important than the inhibition of immunoprecipitation. Clin Exp Immunol. 1990;79:158. doi: 10.1111/j.1365-2249.1990.tb05172.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Klint C, Truedsson L, Sturfelt G. Binding to erythrocyte complement receptor type 1 of BSA/anti-BSA complexes opsonized by C4A3 or C4B1 in the presence of serum. Scand J Immunol. 1995;42:425. doi: 10.1111/j.1365-3083.1995.tb03676.x. [DOI] [PubMed] [Google Scholar]
  • 26.Gibb AL, Freeman AM, Smith RA, et al. The interaction of soluble human complement receptor type 1 (sCRl, BRL55730) with human complement component C4. Biochem Biophys Acta. 1993;1180:313. doi: 10.1016/0925-4439(93)90056-7. [DOI] [PubMed] [Google Scholar]
  • 27.Reilly BD, Skanes VM, Levine RP. Evidence showing that the 1105 and 1106 isotypic residues of the fourth component of human complement, C4A, are not involved in amide bond formation. Mol Immunol. 1994;31:761. doi: 10.1016/0161-5890(94)90150-3. [DOI] [PubMed] [Google Scholar]
  • 28.Dodds AW, Law SKA. Structural basis of the binding specificity of the thioester containing proteins, C4, C3 and alpha-2 macroglobulin. Complement. 1988;5:89. doi: 10.1159/000463039. [DOI] [PubMed] [Google Scholar]
  • 29.Isenman DE, Kells DI. Conformational and functional changes in the fourth component of human complement produced by nucleophilic modification and by proteolysis with Cls. Biochem. 1982;21:1109. doi: 10.1021/bi00535a001. [DOI] [PubMed] [Google Scholar]
  • 30.Roos MH, Mollenhauer E, Dement P, et al. A molecular basis for the two locus model of human complement C4. Nature. 1982;298:854. doi: 10.1038/298854a0. [DOI] [PubMed] [Google Scholar]
  • 31.Reilly BD, Makrides SC, Ford PJ, et al. Quantitative analysis of C4b dimer binding to distinct sites on the C3b/C4b receptor (CR1) J Biol Chem. 1994;269:7696. [PubMed] [Google Scholar]
  • 32.Scatchard G. Ann NY Acad Sci. 1949;51:660. [Google Scholar]
  • 33.Ross GD, Medof ME. Membrane complement receptors specific for bound fragments of C3. Adv Immunol. 1985;37:217. doi: 10.1016/s0065-2776(08)60341-7. [DOI] [PubMed] [Google Scholar]
  • 34.Fearon DT. Regulation of the amplification C3 convertase of human complement by an inhibitory protein isolated from human erythrocyte membrane. Proc Natl Acad Sci USA. 1979;76:5867. doi: 10.1073/pnas.76.11.5867. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Medof ME, Iida K, Mold C, et al. Unique role of the complement receptor CR1 in the degradation of C3b associated with immune complexes. J Exp Med. 1982;156:1739. doi: 10.1084/jem.156.6.1739. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Takata Y, Kinoshita T, Kozono H, et al. Covalent association of C3b with C4b within C5 convertase of the classical complement pathway. J Exp Med. 1987;165:1494. doi: 10.1084/jem.165.6.1494. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Kinoshita T, Takata YU, Kozono H, et al. C5 convertase of the alternative complement pathway: covalent linkage between two C3b molecules within the trimolecular complex enzyme. J Immunol. 1988;141:3895. [PubMed] [Google Scholar]
  • 38.Paccaud JP, Carpentier JL, Schifferli J A. Direct evidence for the clustered nature of complement receptor type 1 on the erythrocyte membrane. J Immunol. 1988;141:3889. [PubMed] [Google Scholar]
  • 39.Reilly BD, Mold C, Levine RP. The isotypes of human C4, C4A and C4B, differ in conformation after proteolytic conversion to C4b by Cls. Mol Immunol. 1993;30:46. [Google Scholar]
  • 40.Masaki T, Matsumoto M, Yasuda R, et al. A covalent dimer of complement C4b serves as a subunit of a novel C5 convertase that involves no C3 derivatives. J Immunol. 1991;147:927. [PubMed] [Google Scholar]
  • 41.Finco O, Li S, Cuccia MC, et al. Structural differences between the two complement C4 isotypes affects the humoral immune response. J Exp Med. 1992;175:537. doi: 10.1084/jem.175.2.537. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Clinical and Experimental Immunology are provided here courtesy of British Society for Immunology

RESOURCES