Reassociation of IgM Subunits in the Presence and Absence of J Chain

Kownatzki, E.

doi:10.3109/08820137309022886

Cited by 50 publications

(17 citation statements)

References 7 publications

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“…Histochemical studies of human immunocytes have indicated that there is great variation between the production of IgA and J chain in individual cells (9,16); similar observations have been made for mouse plasmacytoma cell lines (23,36). There is little definite information available with regard to the mechanism of IgA polymerization, but for IgM it has been shown that the subunits can reassociate in vitro in the absence of J chain (20,29). Moreover, a Jchain-deficient monoclonal IgM protein has been found to consist mainly of hexamers, giving strong support to the possibility that it is a true cellular product (22).…”

Section: Discussionmentioning

confidence: 84%

Complex Formation Between Secretory Component and Human Immunoglobulins Related to Their Content of J Chain

Brandtzæg

1976

Scand J Immunol

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The J-chain content of 3 IgM and 24 IgA preparations was quantitated by an immunochemical technique after reduction with 20mM dithiothreitol. The amounts released ranged from undetectable (less than 0.1 mg) to 7.3 mg per 100 mg of Ig. Most of the J-chain-deficient proteins were monomeric, but four polymeric IgA preparations were found to contain only 0.2-0.8 mg of J chain per 100 mg. The SC-binding capacity of these polymers, expressed as percentage of the amount added (2.5 mu g SC/100 mug Ig), was 6%-12% compared with 69%-82% for IgA and IgM polymers that contained more than 4.0 mg of J chain per 100 mg. Some monomeric IgA preparations showed a slight SC-binding capacity, which was explained by the presence of contaminating J-chain-positive polymers. Bound J chain therefore seems to be a structural prerequisite for a specific noncovalent complexing of Ig polymers with SC.

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Section: Discussionmentioning

confidence: 84%

Complex Formation Between Secretory Component and Human Immunoglobulins Related to Their Content of J Chain

Brandtzæg

1976

Scand J Immunol

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“…On the other hand, IgM hexamers are formed of six monomeric subunits and completely lack J chains (14). The presence of hexameric IgM is confirmed for various human disorders, like cold agglutinin (15,16) and Waldenström's macroglobulinemia (17,18), but it can be also found in normal human sera (19). Except structural differences, two forms of polymeric IgM differ functionally as well.…”

Section: Introductionmentioning

confidence: 88%

Antigenic specificity and expression of a natural idiotope on human pentameric and hexameric IgM polymers

et al. 2011

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Natural antibodies (NAbs) are present in circulation even before the exposure to antigen and they exert various biological functions. They are polyreactive and mainly represented by immunoglobulin M (IgM), which is the first antibody produced in an ongoing immune response to infection and/or immunization. IgM is always secreted as a polymer with predominant pentameric structure, although other polymeric forms such as hexamer can be also formed. The biological functions of hexameric IgM are still not known and it is proposed that its existence as a NAb could be deleterious. However, the nature of IgM hexamers has not been investigated yet. In this paper, we have tested the expression of natural idiotope and antigenic specificities of pentameric and hexameric IgM polymers originating from sera of patients with Waldenström's macroglobulinemia, as well as patients suffering from recurrent urinary bacterial infections. We demonstrate that although pentameric IgM polymers can exist as natural and immune antibodies, IgM hexamers are exclusively immune and do not exist as NAbs.

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“…Although J-chain-negative, hexameric IgM was not the predominant species in the J-chain KO mouse, somewhat surprisingly, hexameric IgM lacking J-chain has been described in normal human sera (25), and is associated with human antibody-related diseases such as Waldenström’s macroglobulinemia, a B cell lymphoma, and cold agglutinin disease (26–28). Additionally, in women vaccinated to uropathogenic bacteria, those that responded to the vaccination had normal levels of pentameric IgM, whereas non-responders had increases in hexameric IgM (29).…”

Section: J-chain Knockout (Ko) Confusionmentioning

confidence: 99%

Putting J Chain Back on the Map: How Might Its Expression Define Plasma Cell Development?

Castro

2014

The Journal of Immunology

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J-chain (Joining chain) is a small polypeptide that regulates multimerization of secretory IgM and IgA, the only two mammalian Igs capable of forming multimers. J-chain also is required for polyIg-receptor (pIgR)-mediated transport of these Ig classes across the mucosal epithelium. It is generally assumed that all plasma cells express J-chain regardless of expressed isotype, despite the documented presence of J-chain-negative plasma cells in mammals, specifically in all monomeric IgA- and some IgG-secreting cells. Compared to most other immune molecules, J-chain has not been extensively studied, due, in part, to technical limitations. Even the reported phenotype of the J-chain knockout mouse is often misunderstood or underappreciated. In this short review, we will discuss J-chain in light of the various proposed models of its expression and regulation, with an added focus on the evolutionary significance of J-chain and its expression in different B cell lineages/differentiation states.

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Reassociation of IgM Subunits in the Presence and Absence of J Chain

Cited by 50 publications

References 7 publications

Complex Formation Between Secretory Component and Human Immunoglobulins Related to Their Content of J Chain

Complex Formation Between Secretory Component and Human Immunoglobulins Related to Their Content of J Chain

Antigenic specificity and expression of a natural idiotope on human pentameric and hexameric IgM polymers

Putting J Chain Back on the Map: How Might Its Expression Define Plasma Cell Development?

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