Variable region genes of anti-HIV human monoclonal antibodies: Non-restricted use of the V gene repertoire and extensive somatic mutation

ABSTRACT Pseudomonas aeruginosa is a significant human pathogen, and no vaccine is commercially available. Passive antibody prophylaxis using monoclonal antibodies (MAb) against protectiveP. aeruginosa epitopes is an alternative strategy for preventing P. aeruginosa infection, but mouse MAb are not suitable for use in humans. Polyclonal human antibodies from multiple donors have variable antibody titers, and human MAb are difficult to make. We used immunoglobulin-inactivated transgenic mice reconstituted with megabase-size human immunoglobulin loci to generate a human MAb against the polysaccharide (PS) portion of the lipopolysaccharide O side chain of a common pathogenic serogroup ofP. aeruginosa, 06ad. The anti-PS human immunoglobulin G2 MAb made from mice immunized with heat-killed P. aeruginosa was specific for serogroup 06ad pseudomonas. The MAb was highly opsonic for the uptake and killing of P. aeruginosa by human polymorphonuclear leukocytes in the presence of human complement. In addition, 25 μg of the MAb protected 100% of neutropenic mice from fatal P. aeruginosasepsis. DNA sequence analysis of the genes encoding the MAb revealed VH3 and Vκ2/A2 variable-region genes, similar to variable-region genes in humans immunized with bacterial PS and associated with high-avidity anti-PS antibodies. We conclude that human MAb to P. aeruginosa made in these transgenic mice are highly protective and that these mice mimic the antibody response seen in humans immunized with T-cell-independent antigens such as bacterial PS.

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Isotype switch variants reveal clonally related subpopulations in diffuse large B-cell lymphoma

Blood ◽

10.1182/blood.v96.7.2550.h8002550_2550_2556 ◽

2000 ◽

Vol 96 (7) ◽

pp. 2550-2556

Author(s):

Christian H. Ottensmeier ◽

Freda K. Stevenson

Keyword(s):

B Cell ◽

Somatic Mutation ◽

Variable Region ◽

B Cell Lymphoma ◽

Immunohistochemical Analysis ◽

Protein Levels ◽

The Status ◽

Aggressive Tumors ◽

Variable Region Genes ◽

Large B Cell

Primary diffuse large B-cell lymphomas (DLBCLs) are aggressive tumors accounting for approximately 40% of B-cell malignancies. The immunoglobulin (Ig) variable region genes have undergone rearrangement and are commonly somatically mutated. The majority show intraclonal variation which indicates that somatic mutation has continued after transformation. Typically, cells of DLBCLs express Ig of a single isotype, but there may be accompanying cells that express alternative isotypes. To probe the status of the isotype switch process in DLBCL, 4 cases of tumor-derived constant region transcripts of all isotypes were investigated. Following the identification of the VDJ sequences, the presence of the major isotype expected from immunohistochemical analysis was confirmed at the RNA level. Another 3-4 alternative isotypes were revealed in all cases, some of which could also be detected by immunohistochemistry. All cases were somatically mutated with an intraclonal variation. In 2 cases there were clearly distinct patterns of somatic mutation between isotypes, which was consistent with independent evolution of the tumor subpopulations. There was apparent clustering of mutational patterns into either an IgMD/IgG3/IgA set or an IgG1/IgA set, indicating that the switch to IgA can occur by different routes. Alternative isotype expression is evident in DLBCL at both the RNA and protein levels. The pattern of mutation indicates that switching is occurring in subpopulations of the tumor after malignant transformation. The findings support the concept that isotype switch events may be a feature of DLBCL.

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Low frequency of somatic mutation in beta-chain variable region genes of human T-cell receptors.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.82.22.7701 ◽

1985 ◽

Vol 82 (22) ◽

pp. 7701-7705 ◽

Cited By ~ 63

Author(s):

K. Ikuta ◽

T. Ogura ◽

A. Shimizu ◽

T. Honjo

Keyword(s):

T Cell ◽

Somatic Mutation ◽

T Cell Receptors ◽

Low Frequency ◽

Variable Region ◽

Beta Chain ◽

Cell Receptors ◽

Human T Cell ◽

Variable Region Genes

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Human immunoglobulin variable region genes: V ? polymorphisms suggest variation in V-gene repertoires

Immunogenetics ◽

10.1007/bf00344034 ◽

1987 ◽

Vol 25 (3) ◽

pp. 193-199 ◽

Cited By ~ 10

Author(s):

Ian F. Turnbull ◽

Kadaba S. Sriprakash ◽

John D. Mathewst

Keyword(s):

Variable Region ◽

Human Immunoglobulin ◽

Immunoglobulin Variable Region ◽

V Gene ◽

Variable Region Genes

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Unmutated Ig VH Genes Are Associated With a More Aggressive Form of Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood.v94.6.1848 ◽

1999 ◽

Vol 94 (6) ◽

pp. 1848-1854 ◽

Cited By ~ 1826

Author(s):

Terry J. Hamblin ◽

Zadie Davis ◽

Anne Gardiner ◽

David G. Oscier ◽

Freda K. Stevenson

Keyword(s):

Chronic Lymphocytic Leukemia ◽

B Cell ◽

Somatic Mutation ◽

Variable Region ◽

Lymphocytic Leukemia ◽

Cell Of Origin ◽

Trisomy 12 ◽

Vh Gene ◽

Vh Genes ◽

Variable Region Genes

Abstract Despite having several characteristics of naı̈ve B cells, chronic lymphocytic leukemia (CLL) cells have been shown in some cases to have somatically mutated Ig variable region genes, indicating that the cell of origin has passed through the germinal center. A previous study of patients with CLL found an association between lack of somatic mutation and trisomy 12 and, therefore, possibly with a less favorable prognosis. We have sequenced the Ig VH genes of the tumor cells of 84 patients with CLL and correlated our findings with clinical features. A total of 38 cases (45.2%) showed ≥ 98% sequence homology with the nearest germline VH gene; 46 cases (54.8%) showed >2% somatic mutation. Unmutated VH genes were significantly associated with V1-69 and D3-3 usage, with atypical morphology; isolated trisomy 12, advanced stage and progressive disease. Survival was significantly worse for patients with unmutated VH genes irrespective of stage. Median survival for stage A patients with unmutated VH genes was 95 months compared with 293 months for patients whose tumors had mutated VHgenes (P = .0008). The simplest explanation is that CLL comprises 2 different diseases with different clinical courses. One, arising from a memory B cell, has a benign course, the other, arising from a naı̈ve B cell, is more malignant.

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