Variation and homology in the mu and gamma heavy chains of human immunoglobulins

Sequence analysis of an 1gM immunoglobulin shows that the variable regions of hunman micro and gamma1 heavy chainis may have twice as much homology as their constant regions and that evolutionary divergence of micro and gamma1 heavy chain genes occurred not long after the separation of heavy and light chain genes.     

Macroglobulin structure: variable sequence of light and heavy chains

The variable regions of the light and heavy chains on the same macroglobulin (immunoglobulin M) molecule are no more related in amino acid sequence than are the variable regions of the light and heavy chains of different immunoglobulin molecules. Subgroups of micro chains are similar in their variable sequence to subgroups of gamma chains.     

Structure of the hinge region of the mu heavy chain of human IgM immunoglobulins

The amino acid sequence around the central disulfide bridge linking the mu heavy chains of the human immunoglobulin M monomer is unlike that in immunoglobulin G. This hinge area contains one of the five oligosaccharides of the mu chain, is low in proline, and is the site of tryptic cleavage to yield Fabmicro and Fcmicro fragments.     

2 types of lambda polypeptide chains in human immunoglobulins

Two antigenic subtypes of human lambda polypeptide chains were distinguished by rabbit antiserum produced to a lambda Bence Jones protein. Lambda Bence Jones proteins and G myeloma proteins with lambda light chains were identified as being in one or the other subtype. The Oz (+) lambda chain subtype is present in light chains from pooled normal human immunoglobulin G and in whole normal immunoglobulin G molecules.     

Evolution of immunoglobulins: structural homology of kappa and lambda Bence Jones proteins

The amino acid sequence of a human lamba chain has been determined. There are many identities in sequence with human kappa chains, but this intraspecies homology is less than the interspecies homology of kappa light chains of man and mouse. Structural relationships suggest a common evolutionary origin and early differentiation of light- and heavy-chain genes.     

Allelic antigenic factor Inv(a) of the light chains of human immunoglobulins: chemical basis

Twenty-seven Bence Jones proteins of immunological type K show a common set of peptides. One 6f the commnon peptides differs in three of the proteins which are the only ones classified by a serological test as Iav(a+). The difference in the peptide analyzed is caused by a valine-leucine interchange; Inv(a+) proteins have leucine, whereas Inv(a-) proteins have valine in position 189.     

Antibody molecules: discontinuous heterogeneity of heavy chains

The heavy polypeptide chains of antibody ( and of gammaG-immnunoglobulin) molecules show discrete bands on disc electrophoresis. The same bands are present for chains from antibodies of the same or diverse specificities. Individual bands are of different intensities for chains from the different rabbits tested even if the antibodies are directed against the same hapten. The bands appear to represent classes of heterogeneous H-chains of the same size having discrete differences in mizobilities with respect to a single charge difference.     

Immunoglobulin structure: variation in amino acid sequence and length of human lambda light chains

Variation and conservation in the primary structure of human lambda light chains is revealed by complete amino acid sequence of three Bence Jones proteins. These proteins differ in amino acid sequence in from 38 to 48 positions; they are of unequal length in the amino-terminal half of the chain but have identical sequence in the last 105 amino acids.     

J genes for heavy chain immunoglobulins of mouse

A 15,8-kilobase pair fragment of BALB/c mouse liver DNA, cloned in the Charon 4A lambda phage vector system, was shown to contain the mu heavy chain constant region (CHmu) gene for the mouse immunoglobulin M. In addition, this fragment of DNA contains at least two J genes, used to code for the carboxyl terminal portion of heavy chain variable regions. These genes are located in genomic DNA about eight kilobase pairs to the 5' side of the CHmu gene. The complete nucleotide sequence of a 1120-base pair stretch of DNA that includes the two J genes has been determined.     

Immunoglobulin M heavy chain disease: intracellular origin of the mu chain fragment

Cells obtained from a patient with mu heavy chain disease synthesize a mu heavy chain fragment with a molecular weight of 55,000. The fragment is detected intracellularly after short labeling times and then is assembled inside the cell and secreted as a disulfide-linked polymer.     

Carboxy-terminal amino acids of gamma-A and gamma-M heavy chains

The carboxy-terminal amino acids of alpha-and micro-chains from human immunoglobulins and alpha-chains from mouse immunoglobulins have been determined by carboxypeptidase digestion and hydrazinolysis. The data suggest the following carboxy-terminal sequences: human micro: Ala-Gly-Thr-Cys-TyrCOOH; human alpha: Thr-Cys-TyrCOOH; murine alpha: (Ileu, Cys)-TyrCOOH.     

Evolution of immunoglobulin polypeptide chains: carboxy-terminal of an IgM heavy chain

The dipeptide sequence at the carboxy-terminal of a heavy (micro) chain from a human macroglobulin ( IgM) is tyrosylcysteine, although the reverse sequence, cysteinyltyrosine, has not been rigorously excluded. The presence of cysteine at the carboxy-terminal was predicted from a recognition of the chemical homologies among the polypeptide chains of immunoglobulins, and their probable evolutionary origin.     

Polypeptide chains of immunoglobulins from the smooth dogfish (Mustelus canis)

The 17S and 7S immunoglobulins of the smooth dogfish, Mustelus canis, have been characterized with respect to molecular weights, chain structure, amino acid composition, and carbohydrate content. The 17S protein had a molecular weight of 982,000; that of the 7S protein was 198,000. Both proteins had similar amino acid compositions and a carbohydrate content of approximately 8 percent. Light and heavy chains from both immunoglobulins had molecular weights of 20,000 and 72,000 respectively. Apparently both immunoglobulins belong to the same class; this class resembles the gammaM-immunoglobulins of higher vertebrates.     

A hidden antigenic site localized to the constrant region of light chains of immunoglobulins

An antigenic site, which was not immunochemically demonstrable in the intact kappa light polypeptide chain, was exposed by enzymatic cleavage of the kappa chain into its variant half and constant half. This antigenic site located in the constant region the kappa chain was detected immunochemically by several antiserums that had specificity for this site. Treatment of an intact kappa chain with a dissociating agent resulted in the exposure of the hidden antigenic site, which was as readily detected in the unfolded polypeptide chain as in the isolated constant half.     

A difference between biological effects of gamma rays and heavy ions

When irradiated with gamma rays, Arteinia eggs show the typical sigmoidal survival curve of a multicellular organism, with little change at low doses and an abrupt decrease in survival above a threshold dose. On irradiation with 160-Mev oxygen ions, the threshold disappears and viability can be destroyed by passage of a single energetic ion.     

Antigenic determinants common to human immunoglobulins G and M: importance of conformational antigens

Antiserums produced against certain isolated human myeloma IgGglobulins and absorbed in order to show only individual antigenic specificity crossreact with certain Waldenstrom IgM-globulins. Some of the common antigenic determinants revealed by these cross-reactions depend on the tertiary and quaternary structure of the IgG and IgM molecules and are independent of their K and L light-chain antigenic types.     

Natural human antibodies to gram-negative bacteria: immunoglobulins G, A, and M

Significant amounts of immunoglobulins G and M, and a small amount of natural antibodies reactive with Neisseria gonorrhoeae and Escherichia coli, have been detected in human adult serums by imnmunofluorescent techniques. Umbilical cord serums also contained substantial immunoglobulin-G antibody but little or no M or A. These findings challenge the concept that natural antibodies reactive with Gram-negative bacteria are primarily of the immunoglobulin-M class.     

Functional interaction and partial homology between human immunodeficiency virus and neuroleukin

Dementia is common in patients with AIDS, but the mechanism by which the human immunodeficiency virus type 1 (HIV-1) causes the neurological impairment is unknown. In this study the possibility that an antigen of HIV-1 suppresses neuronal responses to neurotrophic factors was examined. Both HIV-1 and a related retrovirus, simian immunodeficiency virus (SIV), inhibited the growth of sensory neurons from chick dorsal root ganglia in medium containing neuroleukin (NLK) but not in medium containing nerve growth factor. An unrelated type D retrovirus, simian acquired immunodeficiency syndrome virus, did not affect the growth of neurons in the presence of either neurotrophic factor. The inhibition by HIV-1 of neuron growth in the presence of NLK was found to be due to the gp120 envelope glycoprotein. Regions of sequence homology between gp120 and NLK may account for this inhibitory property of gp120 and functional interactions between gp120 and NLK may be important in the pathogenesis of the AIDS dementia complex.