IMGT Repertoire (IG and TR)

Isotypes: Human (Homo sapiens) IGLC

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The IGL C-REGIONs encoded by 4-5 IGLC genes in the 7-IGLC gene haplotype, belong to four serological isotypic forms. These lambda isotypes differ by limited amino acid substitutions which produce the Oz [1-3], Kern (Ke) [4,5] and Mcg [6,7] serological markers [8,9]:

Mcg⁺ proteins have Asn 1 and Thr 3 (positions according to the IMGT unique numbering for C-DOMAIN) whereas Mcg^- proteins have Ala 1 and Ser 3.
Position 82 initially described as characteristic of the Mcg marker is not involved [9]. Indeed, the protein MOR is different from the other Mcg^- proteins by having Ala 82 [10], and the protein MCP which is Mcg^- Oz^- and is encoded by the IGLC7 gene [11], has Lys 82.
Ke⁺ proteins have Gly 45 whereas Ke^- proteins have Ser 45.
Oz⁺ proteins have Lys 100 whereas Oz^- proteins have Arg 100.

Correspondence between serological lambda isotypes and IGLC gene and allele names [9]

Serological Isotypes	IGLC gene and allele name	Amino acid positions (1)
		1	3	45	82	100
		(6)	(8)	(46)	(57)	(83)
		112	114	152	163	190
Mcg⁺ Ke⁺ Oz^-	IGLC101, 02	Asn AAC	Thr ACG	Gly GGC	Lys AAA	Arg AGA
Mcg^- Ke^- Oz^-	IGLC201, 02, 03 IGLC304 IGLC2D1*01	Ala GCC	Ser TCG	Ser AGC	Thr ACA	Arg AGA
Mcg^- Ke^- Oz⁺	IGLC301, 02, *03	Ala GCC	Ser TCG	Ser AGC	Thr ACA	Lys AAA
Mcg^- Ke⁺ Oz^-	IGLC204 IGLC601	Ala GCC	Ser TCG	Gly GGC	Thr ACA	Arg AGA
Mcg^- Ke⁺ Oz^-	IGLC701, 02, *03	Ala GCC	Ser TCG	Gly GGC	Lys AAA	Arg AGA

IMGT note:
(1)	Amino acid positions according to the IMGT unique numbering for C-DOMAIN (in bold), to the IMGT exon numbering (between parentheses) and to the Kabat numbering (in italics). Whereas the serological markers Mcg, Ke and Oz were initially assigned to Bence-Jones and myeloma proteins using specific antibodies [12]. The antiserum which allowed to recognize Ke⁺ is no longer available. The assignment of the Mcg^- Ke⁺ Oz^- isotype to IGLC gene and allele names is based on the presence or absence of characteristic amino acids [9].

References:
[1]	Apella, E. and Ein, D., Proc. Natl. Acad. Sci. USA, 57, 1449-1454 (1967).
[2]	Ein, D. and Fahey, J.L., Science, 156, 957-950 (1967).
[3]	Ein, D., Proc. Natl. Acad. Sci. USA, 60, 982-985 (1968).
[4]	Ponstingl, H. et al., Hoppe-Seyler's Z. Physiol. Chem., 349, 867-871 (1968).
[5]	Hess, M. et al., Nature New Biol., 234, 58-61 (1971).
[6]	Fett, J.W. and Deutsh, H.F., Biochemistry, 13, 4102-4114 (1974).
[7]	Fett, J.W. and Deutsh, H.F., Immunochemistry, 12, 643-652 (1975).
[8]	Dariavach, P. et al., Proc. Natl. Acad. Sci. USA., 84, 9074-9078 (1987).
[9]	Lefranc, M.P. and Lefranc, G., Immunoglobulin lambda (IGL) genes of human and mouse. In: Molecular Biology of B cells (eds. Alt F., Honjo T. and Neuberger M.S.), Elsevier, London, UK (2003 in press).
[10]	Frangione, B. et al., Proc. Natl. Acad. Sci. USA, 82, 3415-3419 (1985).
[11]	Niewold, T.A. et al., J. Immunol., 157, 4474-4477 (1996).
[12]	Walter, M.R. et al., J. Immunol., 140, 1600-1604 (1988).

See also:

Germline gene table: Human IGLC (IMGT Repertoire)
IMGT gene name nomenclature for IG and TR of human and other vertebrates (IMGT Scientific chart)