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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2008-7-21
pubmed:abstractText
In addition to producing conventional tetrameric IgGs, camelids have the particularity of producing a functional homodimeric IgG type lacking L (light) chains and only made up of two H (heavy) chains. This nonconventional IgG type is characterized by variable and constant regions referred to as V(H)H and C(H)H, respectively, and which differ from conventional V(H) and C(H) counterparts. Although the structural properties of homodimeric IgGs have been well investigated, the genetic bases involved in their generation are still largely unknown. In this study, we characterized the organization of genes coding for the H chains of tetrameric and homodimeric IgGs by constructing an alpaca (Lama pacos) genomic cosmid library. We showed that a single IgH locus in alpaca chromosome 4 contains all of the genetic elements required for the generation of the two types of Igs. The alpaca IgH locus is composed of a V region that contains both V(H)H and V(H) genes followed by a unique D(H)-J(H) cluster and C region genes, which include both C(H)H and C(H) genes. Although this general gene organization greatly resembles that of other typical mammalian V(n)-D(n)-J(n)-C(n) translocon IgH loci, the intermixed gene organization within the alpaca V and C regions reveals a new type of translocon IgH locus. Furthermore, analyses of cDNA coding for the membrane forms of IgG and IgM present in alpaca peripheral blood B cells are most consistent with the notion that the development of a B cell bearing homodimeric IgG passes through an IgM(+) stage, similar to the case for conventional IgG.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1550-6606
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
181
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2001-9
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Tetrameric and homodimeric camelid IgGs originate from the same IgH locus.
pubmed:affiliation
Unité de Génétique et Biochimie du Développement, Département d'Immunologie, Unité de Recherche Associée Centre National de la Recherche Scientifique 2581, Institut Pasteur, Paris, France.
pubmed:publicationType
Journal Article