Univalent fragments of antibody: A study by electron microscopy

Almeida, June D.; Cinader, B.; Naylor, David

doi:10.1016/0019-2791(65)90018-2

Cited by 17 publications

(4 citation statements)

References 17 publications

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“…Thus, GPaGP Sp autoantibodies react with structures of sperm known to participate in a number of prefertilization and fertilization events. The regular space of 15-25 nm that existed between the plasma membrane or the inner acrosomal membrane and the ferritin particles is consistent with the estimated molecular size of IgG molecules (Almeida et al, 1965).…”

Section: Discussionsupporting

confidence: 81%

Sperm autoantigens and fertilization. III. Ultrastructural localization of guinea pig autoantigens

Tung

Yanagimachi

1982

Anat. Rec.

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Guinea pig sperm autoantigens have been localized by direct and indirect immunoferritin techniques in (1) plasma membrane over the entire sperm head, (2) acrosomal contents, (3) fibrous sheath and outer dense fibers of the tail filament, and (4) the inner acrosomal membrane of 50% of acrosome reacted spermatozoa. These cellular structures are known to be involved in guinea pig sperm rouleaux formation, acrosome reaction, interaction of acrosome-reacted sperm with zona pellucida and with the vitellus of guinea pig ova. Since IgG and Fab of autoantiserum to guinea pig spermatozoa have been shown to interfere with these cellular reactions, this study provides further evidence, albeit indirect, that sperm autoantigens are involved in these cellular events.

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Section: Discussionsupporting

confidence: 81%

Sperm autoantigens and fertilization. III. Ultrastructural localization of guinea pig autoantigens

Tung

Yanagimachi

1982

Anat. Rec.

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“…The maximal dimensions of Fab/z fragments, obtained by both methods of papain digestion, were 50 A (length of double chain part) and about 80 A (total length) X 30 A which may be compared with measurements given for Fab% Valentine and Green (31) reported mean Fab'y dimensions of 60 A X 35 A and Almeida et al (32) found Fab~" fragments attached to polyoma virus to have a mean size of 67 A X 25 A. The maximal length measurements given by the two groups were 80 A and 97 A, respectively.…”

Section: Discussionmentioning

confidence: 70%

ULTRASTRUCTURE OF PAPAIN AND PEPSIN DIGESTION FRAGMENTS OF HUMAN IgM GLOBULINS

Svehag

Bloth

Séligmann

1969

The Journal of Experimental Medicine

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Considerable information on the structure and antibody activity of IgM globulins has been obtained recently. Miller and Metzger (1) and Lamm and Small (2) proposed that the IgM molecule is composed of five 7S subunits, each of which is probably linked by a single disulfide bond to the adjacent subunit (3). Ultrastructural studies of human and rabbit IgM confirmed this five subuuit model (4, 5) and showed that subunits joined in a central ring structure form a circular pentamer. 10 potential combining sites have been predicted from polypeptide chain construction studies (2, 3, 7) and analyses of trypsin digestion fragments of IgM (6). IgM antibodies to a tetrasaccharide antigen of Salmonella typhi and a hapten were recently reported (8, 9) to have valences of 10. Other investigators (10-12) have however been unable to demonstrate more than five effective valences. Recent ultrastructural studies (13) also indicated that the human IgM subunits were univalent.IgG is cleaved by papaha into three distinct fragments: two Fab fragments, each containing one light chain and part of a heavy chain and one Fc fragment containing the remainder of the heavy chains (14). IgM molecules can also be degraded by papain into molecules of lower molecular weight (15-21). Deutsch et at. (15), using papain activated by 0.01 ~ cysteine, obtained no Fc-like fragments, while Onone et al. (18) reported that papain digestion of reduced IgM subunits resulted in a small yield of Fc-like fragments. Recently papain cleavage of intact IgM has yielded small amounts of larger Fc/z fragments (16,17,(19)(20)(21). All these studies indicate, that unlike the stability of the Fc fragment of IgG, its counterpart of both human and rabbit IgM is rather rapidly hydrolyzed to dialyzable peptides.The cleavage of IgM globulins by pepsin has been investigated recently (22-24). A dimeric F(ab")~ fragment was obtained only under mild conditions of proteolysis. The pepsin digestion proceeded rapidly over a monomeric Fab'/z fragment to a complete conversion into small peptides within 48 hr. The C-terminal portion of the #-chains in the IgM molecule corresponding to the papain Fc/z fragment was rapidly digested into small peptides.

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“…Evidence consistent with the occurrence of conformative response in antibodies has been available for some years (8,224,645,821,843). The phenomenon of stabilization of antibodies by antigens, and more significantly perhaps, by haptens, is quite familiar (e.g., ref.…”

Section: A Is Conformative Response Necessary?mentioning

confidence: 88%

Conformational Adaptability in Enzymes

Citri¹

1973

Advances in Enzymology - And Related Areas of Molecular Biology

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Univalent fragments of antibody: A study by electron microscopy

Cited by 17 publications

References 17 publications

Sperm autoantigens and fertilization. III. Ultrastructural localization of guinea pig autoantigens

Sperm autoantigens and fertilization. III. Ultrastructural localization of guinea pig autoantigens

ULTRASTRUCTURE OF PAPAIN AND PEPSIN DIGESTION FRAGMENTS OF HUMAN IgM GLOBULINS

Conformational Adaptability in Enzymes

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