Disease relevance of BF2

• In this study, an avian leukosis virus (ALV) vector system, RCASBP, expressing MHC chicken class I (B-F) cDNA was used to develop target cells expressing the chicken class I glycoproteins complexed with ALV antigens on the cell surface [1].
• A btuB::Tn10 insertion which disrupts the gene encoding the vitamin B12 receptor from E. coli K-12 was P1 transduced into a virulent E. coli K1 strain [2].
• Marek's disease virus down-regulates surface expression of MHC (B Complex) Class I (BF) glycoproteins during active but not latent infection of chicken cells [3].
• The peptide binding motifs for this major B-F12 molecule in chickens of Rous sarcoma regressor line CB (B12/B12) have been determined [4].
• Clinically significant vitamin B12 deficiency secondary to malabsorption of protein-bound vitamin B12 [5].

Psychiatry related information on BF2

• The results of this series of experiments with chicks trained on a single trial, passive avoidance task, demonstrate that methotrexate-induced folate deficiency, and excess levels of folate and B12 lead to amnesia in these subjects [6].

High impact information on BF2

• Evidence is presented that the immune response to B-G antigens is responsible for the development of autoimmunity and other pathological events that follow and that tolerance to class I MHC antigens (B-F antigens) shared by lymphocytes erythrocytes is maintained at the same time that B-G tolerance is broken [7].
• This transcript, that is by far the most divergent known member of the class I gene family, hybridized to six B-F genes present in the cosmids [8].
• Second, we find, for the B4, B12, and B15 haplotypes, that one cDNA is at least 10-fold more abundant than the other [9].
• Compared with the MHC of typical mammals, the chicken MHC is smaller and simpler, with only two class I genes found in the B12 haplotype [9].
• The kinetics of the reaction of cyanide with free aquocobalamin (H2OCbl) and with aquocobalamin bound to a vitamin B12-binding protein (haptocorrin) from chicken serum (HC-H2OCbl) have been investigated as a function of temperature and pH [10].

Chemical compound and disease context of BF2

• The addition of choline, riboflavin, vitamin B12, vitamin A or E, folic acid, or biotin did not increase weight gains [11].
• The use of this RIA, together with an assay for plasma methylmalonic acid, in the diagnosis of cobalt/vitamin B12 deficiency in sheep is described [12].

Biological context of BF2

• The major histocompatibility complex B (MHC B) region in a standard haplotype of Leghorn chickens contains two closely linked class I loci, B-FI and B-FIV [13].
• Genotyping of the F2 chickens for Rfp-Y haplotypes was performed by restriction fragment length polymorphism analysis of genomic DNA using TaqI and a B-FIV probe [14].
• A cosmid fragment has been used to isolate a cDNA for a class I (B-F) transcript [8].
• BF residues 78 and 81, corresponding to HLA 79 and 82, form an antibody epitope with a slight effect on ALV antigen presentation, consistent with their predicted orientation based on the HLA-A2 crystal structure [15].
• Functional analysis of avian class I (BFIV) glycoproteins by epitope tagging and mutagenesis in vitro [15].

Anatomical context of BF2

• B-FIV amino acid residues predicted to interact with the CDR1alpha region of the T-cell receptor (Tcr) demonstrate less variability than in mouse and human class I alleles [16].
• Functional analysis employing site-directed mutagenesis identified BF amino acid residues forming serologic epitopes as well as residues important in antigen presentation to ALV-induced cytotoxic T lymphocytes [15].
• The chicken major histocompatibility complex (MHC) is commonly defined by serologic reactions of erythrocytes with antibodies specific to the highly polymorphic MHC class I (BF) and MHC class IV (BG) antigens [17].
• These studies demonstrate that following transepithelial flux of vitamin B12 through the ileal mucosa, the vitamin becomes coupled to TCII [18].
• Two of these classes are homologous to classes I and II of mammals (B-F and B-L, respectively), while the third (B-G) is a differentiation antigen of the erythroid cell-line; the mammalian homologue of this class is still undefined [19].

Associations of BF2 with chemical compounds

• Monoclonal antibodies to the FLAG epitope served to monitor cell-surface expression for functional analysis of the BFIV21 class I glycoprotein [15].
• Parenteral injection of 1000 microgram of nonlabeled vitamin B12 did not interfere with the absorption of the radio-B12 from the meat [20].
• We demonstrate here that B-G molecules purified with monoclonal antibodies exert this adjuvant effect on the production of alloantibodies to chicken class I (B-F) molecules, when the two are in the same liposome [21].
• MDV-induced T-cell tumors suffer a nearly complete loss of cell surface BF upon virus reactivation with 5-bromo-2'-deoxyuridine (BUdR) [3].
• A study was made of the effect of low-dose gamma irradiation on the content of thiamine (B1), riboflavin (B2), niacin, pyridoxine (B6) and cobalamin (B12) in pork chops, and thiamine, riboflavin and niacin in chicken breasts [22].

Other interactions of BF2

• The humoral response of 1 pair of recombinants isolated from a Red Jungle Fowl (BW3 and BW4) being identical on BF and BG, but different on BL, indicated that part of the primary vaccine response was an MHC II restricted T-cell dependent response [23].
• The MHC of a broiler chicken line: serology, B-G genotypes, and B-F/B-LB sequences [24].

Analytical, diagnostic and therapeutic context of BF2

• Third, we use 2D gel electrophoresis of class I molecules from pulse-labeled cells to show that there is only one heavy chain spot for the B4 and B15 haplotypes, and one major spot for the B12 haplotype [9].
• The B serotypes were compared by B-G restriction fragment length polymorphism (RFLP) analysis, allele-specific PCR typing test for B-LBII family genes and nucleotide sequence analysis of expressed B-F and B-LBII family genes [25].
• Subsequently, the monomers were further separated, and the purified MBP-BF2, -beta2m, and MBP were analyzed by circular dichroism (CD) spectrum [26].
• A vitamin B12-binding protein (haptocorrin) from chicken serum has been purified to homogeneity by photodissociative affinity chromatography and characterized by gel electrophoresis and UV-visible spectrophotometry of its aquocobalamin, hydroxocobalamin, and cyanocobalamin complexes [27].
• The urinary radioactivities, which were as low as those after oral administration of radioactive hydroxocobalamin and vitamin B12 coenzyme, suggested that the radio-B12 was present in meat in coenzyme form or was converted into the stable hydroxoform during the process of cooking and digestion [20].

References