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Immunogenicity of a free synthetic peptide: carrier-conjugation enhances antibody affinity for the native protein
No full textThe synthetic peptide 166-174 of hCS sequence, corresponding to an antigenic determinant of the protein, was used to elicit MAbs to the native hCS molecule. The synthetic peptide was administered according to different immunization protocols to BALB/c mice, both in the free form or conjugated to carrier proteins. Spleens and popliteal lymph nodes from primed mice were fused with a myeloma cell line to produce MAbs, and selected clones were characterized for isotype and affinity. Spleen fusions gave rise to IgM MAbs, whereas lymph node fusions gave preferentially IgG MAbs. No correlation was found between antibody class and affinity since affinity is highly increased by carrier-conjugation, while it did not enhance IgG production. The free synthetic peptide showed a low immunogenicity: affinities of MAbs produced ranged from 10(5) to 10(7) l/mole, an average 1000-fold lower than the values obtained with carrier-conjugated peptide. In one case, however, carrier conjugation did not give rise to anti-hCS MAbs. Overall, these studies provide a rational approach to the production of anti-protein MAbs by synthetic peptide immunization and offer the opportunity to obtain MAbs of the desired isotype and affinity
Interaction of the human immunodeficiency virus type-1 envelope glycoprotein gp120 with a galactoglycerolipid associated with sperm
No full textThe expression of a molecule recognized by anti-galactosyl ceramide antibodies (MAb) O1 on the surface membrane of human spermatozoa was investigated by biochemical and immunochemical methods. Indirect immunofluorescence shows that this molecule is preferentially localized on the middle piece of the sperm tail, Immune-thin-layer chromatography has identified it as a glycolipid related but not identical to galactosylceramide. Consistent with a structure similar to galactosylceramide, the sperm glycolipid is capable of binding gp120. An improved ELISA has been utilized to demonstrate the specificity of binding of the antibodies and gp120 to the isolated lipid fraction, Identity of the binding site of the two ligands to the glycolipid is suggested by competition assays. On the basis of preliminary biochemical analysis this glycolipid was tentatively classified as a galactosylalkylacylglycerolipid (GalAAG), the nonsulfated form of the seminolipid, a glycolipid known to be present in the testis and germ cells of mammals. These data indicate that human sperm express a glycolipid similar in structure to the receptor for HIV described on the CD4(-) neural and colonic epithelial cell Lines, and moreover suggest that this glycolipid could also function as HIV receptor and possibly be implicated in its transmission
Human sperm and spermatogonia express a galactoglycerolipid which interacts with gp120
No full textSexual transmission is a major mode of spread of HIV-1 although the mechanisms involved remain to be elucidated. The role of spermatozoa as carriers of the HIV is supported by recent publications, while the expression of the CD4 on the membrane of the sperm has not yet been demonstrated. The data reported in this paper show that a glycolipid molecule, most likely the galactosyl-alkyl-acylglycerol, structurally similar to galactosylceramides, is present on the surface membrane of the spermatozoa. Consistent with a structure similar to galactosylceramide, the sperm glycolipid is capable of binding the gp120 as demonstrated utilizing an improved ELISA assay which favors sensitivity and specificity. Immunocytochemistry of testicular tissue shows the presence of this glycolipid on the membrane of immature germ cells, preferentially in the spermatogonia. These data indicate that human sperm express a glycolipid similar in structure to the receptor for HIV described on the CD4- neural and colonic epithelial cell lines, and moreover suggest that this glycolipid could also function as HIV receptor and possibly be implied in its transmission. The demonstration that this molecule is also expressed by the spermatogonia suggests its involvement in the interaction of the HIV with spermatogonia, as recently reported, and could explain the inhibition of spermatogenesis observed in AIDS patients
New insights into the interaction between the Galactosyl-alkyl-acyl-glycerol and GP120 in human sperm
No full textProduction and characterization of monoclonal antibodies to anti-human chorionic somatomammotropin by immunization with two free synthetic peptides.
No full textThe peptides corresponding to the fragments 135-140 and 166-174 of human chorionic somatomammotropin (hCS) were synthesized, and used to raise monoclonal antibodies to the native hCS molecule. The synthetic peptides were injected into BALB/c mice in the free form, i.e. not conjugated to a carrier, and the spleens were fused with Sp2/01Ag8 myeloma line to produce monoclonal antibodies. The antibodies produced belonged to the IgM and IgG classes and, once purified by affinity chromatography on hCS-Sepharose, they were covalently coupled to macroporous polystyrene beads and characterized by competitive radioimmunoassay. Their affinity constants were determined by elaborating the radioimmunoassay data by nonlinear regression analysis and they were found to range from 10(5) to 10(6) M-1. The evaluation of the affinity constant of the antibodies produced is always important as a measure of the immunogenicity of an antigen, particularly when synthetic peptides are used as immunogens
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Metabolic behavior and distribution of the synthetic nonapeptide fragment 163-171 of human IL-1 beta
No full textThe pharmacokinetic parameters and distribution of the adjuvant synthetic nonapeptide VQGEESNDK, corresponding to the fragment in position 163-171 in human IL-1, were analyzed after administration to rabbit through different routes. The radiolabeled peptide did not bind to plasma proteins and, when inoculated i.v., it disappeared very rapidly from the circulation, with a t1/2 alpha of 1 min and a t 1/2 beta of 166 min. Upon administration through i.m., s.c. and oral route, the Cmax was reached between 30 and 90 min after inoculum and ranged between 7 and 4% of the administered dose. Organ distribution showed that most of the radioactivity was concentrated in kidneys and excreted in urine. From Sephadex G-10 chromatography, about 60% of the peptide recovered in the urine 4h after i.v. inoculum was intact, whereas it was more than 85% degraded when administered by other routes. The amount of intact peptide recovered in the urine correlated with the biological effectiveness through different routes, suggesting that the adjuvant effect in vivo is exerted by the intact peptide, rather than by its metabolites
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