RESUMO
The variable heavy and light chain genes of a monoclonal, IgM, anti-MAG antibody from a patient with neuropathy were inserted into expression vectors containing the gamma and kappa constant regions respectively and co-transfected into monkey kidney CV1P cells. The expressed antibody had the same antigenic specificity but significantly lower avidity than the native IgM, anti-MAG, antibody as detected by ELISA. When the variable heavy chain gene of the anti-MAG antibody was co-transfected with the variable light chain gene from another monoclonal, IgM, anti-MAG antibody, a fully assembled antibody was expressed as determined by a trapping ELISA, but it did not bind to (MAG) or to sulfated glucuronic acid paragloboside, indicating that both heavy and light chains contribute to the binding activity.
Assuntos
Anticorpos Monoclonais/genética , Proteínas da Mielina/imunologia , Animais , Afinidade de Anticorpos , Especificidade de Anticorpos , Sequência de Bases , Linhagem Celular , DNA/genética , Expressão Gênica , Genes de Imunoglobulinas , Humanos , Imunoglobulina M/genética , Dados de Sequência Molecular , Glicoproteína Associada a Mielina , TransfecçãoRESUMO
The complete variable heavy and light chain gene sequences of two monoclonal, IgM, anti-myelin associated glycoprotein (MAG) antibodies associated with peripheral neuropathy, are presented. Comparative analysis of the two VH regions has revealed that they are 88% homologous to one another and are both members of the VH3 gene family. They are also highly homologous to a gene which is frequently utilized in the fetal B-cell repertoire. The V kappa light chain gene of one of the antibodies is 99% homologous to a V kappa II gene and the V lambda light chain gene of the other antibody is only 72% homologous to other known V lambda genes. Further analysis of V genes utilized by anti-MAG antibodies should reveal the structural basis for their binding activity.
Assuntos
Anticorpos Monoclonais/genética , DNA/genética , Imunoglobulina M/genética , Proteínas da Mielina/imunologia , Bainha de Mielina/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Sequência de Bases , Northern Blotting , Rearranjo Gênico , Humanos , Dados de Sequência Molecular , Glicoproteína Associada a MielinaRESUMO
We have cloned and determined the nucleotide sequence of the Ig VH and VL region genes of an IgM kappa mAb that binds to denatured DNA and myelin from a patient (POP) with chronic lymphocytic leukemia and peripheral neuropathy. Sequence analysis indicates that the V region of the kappa L chain gene (PopVK) has 99% homology to a V kappa IIIa germ-line gene and the V region of the mu H chain gene (PopVH) has 96% homology to the VH26 germ-line gene that is a member of the VH3 gene family. It is likely the V kappa and VH genes arose from these respective germ-line genes via somatic mutation or from closely related genes. V kappa III genes have frequently been used by other IgMk mAb especially those with rheumatoid factor activity, and the VH26 gene with no somatic mutation has been used by several anti-DNA antibodies, suggesting the possibility of preferential association of these or related germ-line genes with autoantibodies. The minor differences between the sequences of POP's VH and V kappa genes and sequences used by other autoantibodies, may be responsible for this antibody's crossreactivity with myelin and, as a result, the autoimmune neuropathy.
Assuntos
Anticorpos Antinucleares/genética , Autoanticorpos/genética , Genes de Imunoglobulinas , Região Variável de Imunoglobulina/genética , Leucemia Linfoide/genética , Bainha de Mielina/imunologia , Doenças do Sistema Nervoso Periférico/genética , Sequência de Aminoácidos , Anticorpos Monoclonais/genética , Sequência de Bases , Southern Blotting , Clonagem Molecular , Humanos , Cadeias kappa de Imunoglobulina/genética , Cadeias mu de Imunoglobulina/genética , Dados de Sequência Molecular , Doenças do Sistema Nervoso Periférico/imunologia , RNA Mensageiro/genéticaRESUMO
Creatine kinase (CK) isoenzymes were determined on 15 patients undergoing open heart surgery with bypass. The study was performed to examine the relationship between the hypothermia under which the surgery is conducted and the appearance of CK isoenzymes in the serum both during and after surgery. All patients showed dramatic rises in total CK activity commencing during surgery. Myocardial CK (CK-MB or CK-2) was seen in fourteen patients and brain CK (CK-BB or CK-1) was seen in ten patients. Peak activities of CK-BB did not coincide with peak activities of CK-MB. The serum elevations of CK-BB in these patients appear to arise from a mechanism different from that responsible for the elevations of CK-MB, and it is assumed that the former is due to intermittent disruptions in the perfusion and/or oxygenation of tissues rich in CK-BB. CK-MB elevations appear to be due directly to the surgical intervention. Hypothermia alone does not in itself appear to be solely responsible for elevations of CK-BB although it can not be completely excluded from playing some role in its production.