Antibody levels against alpha-galactosyl epitopes in sera of patients with squamous intraepithelial lesions and early invasive cervical carcinoma

Anti α1-3Gal antibodies and Gal content in gut microbiota in immune disorders and multiple sclerosis

Recent observations suggest that Gal antigen content in gut microbiota and anti-Gal antibody response may influence inflammation in immune related disorders. In this review we summarized the current knowledge on antibody response to the Gal epitope in various immune disorders. We discuss the origin of Gal antigen associated to gut microbiota. In multiple sclerosis, the possible mechanisms by which the altered microbiota and/or circulating anti-Gal level could affect the immune response in this disease are presented.

Natural IgG antibody with anti-β-galactosyl specificity suppressed hepatoma cell invasion in culture

The effect of natural IgG antibody recognizing β-galactosyl epitope on hepatoma cell invasion was investigated. Anti-β-galactosyl antibody dose-dependently suppressed hepatoma invasion underneath primarily cultured mesothelial cells monolayer without affecting the proliferation, to the same extent as natural IgG antibody with anti-α-galactosyl specificity, which had already been reported to have an anti-metastatic activity. The inhibitory effect of anti-β-galactosyl antibody was completely canceled by adding lactose (galactose-β-1, 4-glucose) to the medium, indicating that this antibody recognized some antigens with β-galactosyl epitope. Hepatoma cells pretreated with this antibody for 48 h showed reduced invasive activity, while the pretreatment of mesothelial cells with the antibody did not affect hepatoma cells invasion. Anti-β-galactosyl antibody also suppressed hepatoma cells adhesion to mesothelial cells monolayer. These results suggest that natural antibody with anti-β-galactosyl specificity may recognize the β-galactosyl epitope in some adhesion-related molecules on hepatoma cells, thus suppressing adhesion and invasion to mesothelial cells monolayer. These results suggest possible therapeutic uses of this antibody in the treatment of metastatic tumors.

Anti-alphaGal-dependent complement-mediated cytotoxicity in metastatic melanoma

Antibodies to the cell surface disaccharide galactose(alpha1,3)galactose (alphaGal) are the most prevalent natural antibodies in human serum. The anti-alphaGal immunoglobulin M-dependent activation of complement causes hyperacute rejection of organ transplants from discordant species by human recipients. It has been shown in vitro that human tumour cells transduced with the gene that synthesizes alphaGal become sensitive to human serum. A prerequisite for anti-alphaGal antibody-based therapeutic strategies is that patients with cancer have adequate serum levels of anti-alphaGal immunoglobulins and complement. The objective of this work was to measure the levels and function of anti-alphaGal immunoglobulins and complement in the serum of patients with metastatic melanoma and healthy volunteers. Serum complement levels were assayed by radial immunodiffusion. Anti-alphaGal immunoglobulin G and immunoglobulin M titres were measured by enzyme-linked immunosorbent assay. Disaccharide sugar blocking was used to investigate antibody specificity. The functional integrity of anti-alphaGal antibodies and complement was investigated in cell lysis assays. It was found that the levels of the complement components C1q, C3 and C4 and the function of the classical complement pathway were normal in metastatic melanoma patients. Anti-alphaGal antibody titres were as variable in metastatic melanoma patients as in healthy controls, and the lysis of alphaGal-expressing cells correlated with anti-alphaGal immunoglobulin M titre (P < 0.0001). Anti-alphaGal antibody titres, complement levels and overall cytolytic function in the serum of patients with metastatic melanoma were indistinguishable from those of healthy controls. There is thus nothing intrinsic to the disease that will limit anti-alphaGal-based therapeutic strategies for enhanced antigen presentation or induced cell lysis, including the mimicry of hyperacute rejection.

Outline of a Risk Assessment: The Welfare of Future Xeno-Donor Pigs

The welfare of transgenic animals is often not considered prior to their generation. However, we demonstrate here how a welfare risk assessment can be carried out before transgenic animals are created. We describe a risk assessment identifying potential welfare problems in transgenic pigs generated for future xeno-donation of organs. This assessment is based on currently available information concerning transgenic animal models in which one or more transgenes relevant to future xeno-donation have been inserted. The welfare risk assessment reveals that future xeno-donor pigs may have an increased tendency toward septicaemias, reduced fertility and/or impaired vision. The transgenic animal models used in generating hypotheses about the welfare of xeno-donor pigs can also assist in the testing of these hypotheses. To ensure high levels of welfare of transgenic animals, analogous risk assessments can be used to identify potential welfare problems during the early stages of the generation of new transgenic animals. Such assessments may form part of the basis on which licenses to generate new transgenic animals are granted to research groups.

Induction of cytolytic anti-Gal antibodies in alpha-1,3-galactosyltransferase gene knockout mice by oral inoculation with Escherichia coli O86:B7 bacteria

Naturally occurring antibodies against [Gal alpha-1,3-Gal] structures (anti-Gal antibodies) are the primary effectors of human hyperacute rejection (HAR) of nonhuman tissue. Unlike most mammals, humans lack a functional alpha-1,3-galactosyltransferase (GalT) gene and produce abundant anti-Gal antibodies, putatively in response to GalT(+) enteric bacteria. GalT knockout (KO) mice have been generated as a small animal model of HAR but inconsistently express anti-Gal antibodies. We hypothesized that enteric exposure of GalT KO mice to live GalT(+) bacteria would produce cytolytic anti-Gal antibodies. Naive mice lacking anti-Gal antibodies were orally immunized with 10(10) live GalT(+) Escherichia coli O86:B7 bacteria and assayed for anti-Gal antibody titer, isotype, and cytolytic activity. Fecal samples were tested for E. coli O86:B7 prior to and after inoculation. In two separate experiments, 77 to 100% (n = 31) of mice developed serum anti-Gal immunoglobulin G (IgG; titer, 1:5 to 1:80) and/or anti-Gal IgM antibodies (titer, 1:5 to 1:1,280) 14 days postinoculation. Induced anti-Gal antibodies caused complement-mediated cytolysis of GalT(+) target cells, with extensive cytolysis observed consistently at serum IgM titers of >/=1:320. Absorption with synthetic [Gal alpha-1,3-Gal] inhibited both antibody binding and cytolysis. E. coli O86:B7 was recovered from stool samples from 83 to 94% of inoculated mice but not from naive mice, thus confirming enteric exposure. These findings demonstrate that oral inoculation with E. coli O86:B7 is a novel and effective method to induce cytolytic anti-Gal antibodies in GalT KO mice and support the premise that enteric exposure to GalT(+) bacteria induces anti-Gal antibodies in humans. These studies also suggest a role for GalT KO mice in elucidating anti-Gal responses in microbial immunity.

Antibody levels against galactosyl (alpha1 --> 3) galactose epitopes in cervical mucus from patients with human papillomavirus infection

OBJECTIVES

The general objective of the present study is to quantify antigalactosyl (alpha1 --> 3) galactose (anti-Gal) antibody levels in the cervical mucus of patients with/without human papillomavirus (HPV) infection and, as specific objectives, to compare these levels in the different HPV subgroups and with the presence of intraepithelial lesions.

METHODS

Sixty women between 18 and 35 years old (mean: 26 years) were studied through the following methods: vaginal cytology, colposcopy, biopsy of suspicious lesions, sample taking for evaluating HPV presence through PCR and hybridization, and quantification of anti-Gal levels using ELISA with laminin antigen extracted from the Engelbreth-Horm-Swarm cell line.

RESULTS

The presence of HPV was detected in 55% of patients; 45% of them had intermediate/high oncogenic risk HPV, 12% had low oncogenic risk HPV, and the other 43% had both subgroups. There were significantly higher anti-Gal levels in the HPV+ group when compared with the HPV- group (P < 0.0001); also, when dividing the HPV+ group into one subgroup with normal cytology and another with cervical intraepithelial neoplasia (CIN) 1, we found higher values in the latter group (P < 0.0001). There was no significant difference in anti-Gal levels in the various HPV subgroups.

CONCLUSION

High anti-Gal levels are found in the cervical mucus of patients with HPV infection and CIN 1, which suggests the participation of local humoral immunity in cervical lesions.