scholarly journals Somatically mutated forms of a major anti-p-azophenylarsonate antibody variable region with drastically reduced affinity for p-azophenylarsonate. By-products of an antigen-driven immune response?

1987 ◽  
Vol 166 (5) ◽  
pp. 1456-1463 ◽  
Author(s):  
T Manser ◽  
B Parhami-Seren ◽  
MN Margolies ◽  
ML Gefter
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Cell Division ◽  
B Cells ◽  
Clonal Selection ◽  
Variable Region ◽  
Antigen Binding ◽  
V Region ◽  
By Products ◽  
Selection Of

The pivotal role played by antigen in the clonal selection of B cells for initial participation in an immune response is well established. Antigen selective mechanisms ensure that antigen-binding antibodies are produced during all stages of the immune response. However, antibodies that lack specificity for the immunogen might also be produced during the course of an antigen-driven immune response . It has been suggested that, through idiotype-antiidiotype network interactions within the immune system, production of antibodies that lack specificity for the immunogen but that share idiotopes with antigen-binding antibodies could result (1). In addition, data obtained by a number of investigators suggest that somatic mutation of antibody V region genes occurs at a rate of 10(-3)/basepair/cell division in B cells participating in an immune response (2, 3). One outcome of such V region structural alteration could be antibodies that lack, or have drastically reduced affinity for the immunogen . We sought to identify and characterize some of the antibody by-products of the antigen-driven immune response that are expected to be created by the mechanisms described above.

scholarly journals Somatic diversification and selection of immunoglobulin heavy and light chain variable region genes in IgG+ CD5+ chronic lymphocytic leukemia B cells.

1995 ◽  
Vol 181 (4) ◽  
pp. 1507-1517 ◽  
Author(s):  
S Hashimoto ◽  
M Dono ◽  
M Wakai ◽  
S L Allen ◽  
S M Lichtman ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
Gene Segment ◽  
Variable Region ◽  
Lymphocytic Leukemia ◽  
Somatic Diversification ◽  
V Region ◽  
Variable Region Genes ◽  
Selection Of ◽  
Antigen Selection

Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of CD5-expressing B lymphocytes. Most studies have found that these leukemic CD5+ B cells, like their normal counterparts, use immunoglobulin (Ig) variable (V) region genes that exhibit minimal, if any, somatic diversity. These and other observations have suggested that CD5+ B cells may be incapable of generating Ig V gene diversity, and therefore may not be able to develop higher affinity binding sites that could be selected by antigen. However, most of the studies of CLL and normal CD5+ B cells have focused on IgM-producing cells. Since somatic mutations are most often seen in B cells that have undergone an isotype class switch, we analyzed the Ig heavy (H) and light (L) chain variable region genes of seven IgG+CD5+ CLL B cells to determine if somatic diversification and antigen selection had occurred. The data derived provide evidence for skewed use, somatic diversification, and antigenic selection of the Ig V region genes. Nonrandom use of both H and L chain V region genes was manifested by an overrepresentation of VH4 and VKI family genes and the underrepresentation of the JH4 gene segment. Furthermore, VH4 gene use was restricted to only two family members (4.21 and 4.18). In four of the seven cases, the VH and VL genes displayed > or = 5% difference from the most homologous known germline counterparts. Polymerase chain reaction and Southern blot analyses performed in two of these patients demonstrated that their unique VH CDR2 and adjacent sequences were not present in their germline DNA. In addition, a significant level of diversity was seen in the rearranged DJH segments and at the VL-JL junctions of every patient that occurred both at the time of recombination and subsequently. The localization of replacement changes to complementarity determining regions of some patients suggested that antigen selection had occurred. Furthermore, the mutations identified in the VH and VL genes of each individual patient were strikingly similar, both in number and location. Collectively, the data indicate that a subset of CD5+ CLL B cells can display Ig V region gene mutations. In addition, they are consistent with the notions that in some cases antigen selection of these mutations may have occurred, and that antigen stimulation may be a promoting factor in the evolution of certain CLL clones.

scholarly journals Different epitope structures select distinct mutant forms of an antibody variable region for expression during the immune response.

1991 ◽  
Vol 173 (3) ◽  
pp. 665-672 ◽  
Author(s):  
S Fish ◽  
M Fleming ◽  
J Sharon ◽  
T Manser
Keyword(s):  
Immune Response ◽  
Amino Acid ◽  
Somatic Mutation ◽  
Amino Acid Substitution ◽  
Variable Region ◽  
Single Amino Acid ◽  
Amino Acid Residues ◽  
V Region ◽  
Mutant Forms ◽  
Selection Of

Antibody variable (V) regions that initially differ from one another by only single amino acid residues at VH-D and D-JH segment junctions (termed canonical V regions) can be elicited in strain A/J mice by three different haptens. Among such V regions an amino acid substitution due to somatic mutation is recurrently observed at VH CDR2 position 58, regardless of which of these haptens is used for immunization. This substitution confers upon a canonical V region a generic increase in affinity for all the haptens. Conversely, the type of amino acid substitution at VH position 59 resulting from somatic mutation that is recurrently observed among such V regions changes with the eliciting hapten, in a manner that correlates directly with the cognate affinity increases (or decreases) for hapten conferred by the observed substitutions. This small subregion of VH CDR2 therefore plays a major role in determining both affinity and specificity for antigen. The data confirm that affinity for antigen is of pivotal importance in determining the degree of selection of different mutant forms of a V region. Moreover, during an immune response a sufficiently diverse mutant repertoire can be generated from a single canonical V region to allow adaptation to increase affinity for three different epitopes.

scholarly journals Tracing the development of single memory-lineage B cells in a highly defined immune response.

1996 ◽  
Vol 183 (5) ◽  
pp. 2053-2063 ◽  
Author(s):  
A H Liu ◽  
P K Jena ◽  
L J Wysocki
Keyword(s):  
Immune Response ◽  
B Cells ◽  
B Lymphocyte ◽  
Clonal Selection ◽  
Germinal Centers ◽  
Primary Immune Response ◽  
Taq Polymerase ◽  
Predominant Component ◽  
V Genes ◽  
V Gene

To study the development of B lymphocyte memory, we identified and isolated splenic B cells expressing a highly defined antibody variable region that constitutes a reproducible and predominant component of the memory antibody response to p-azophenylarsonate (Ars). Isolation was achieved during the primary immune response by surface staining and flow cytometry using a specific anti-idiotypic antibody called E4, which recognizes this canonical V region, encoded by one set of V gene segments. The isolated E4+ cells displayed all of the phenotypic characteristics of germinal center centrocytes, including a low level of surface Ig, a lack of surface IgD, a high level of receptor for peanut agglutinin, and expression of mutated antibody V genes. E4+ B cells were first detected in the spleen 7-8 d after primary immunization, reached peak numbers from days 10-13, and waned by day 16. Surprisingly, at their peak, E4+ cells comprised only 40,000 of all splenocytes, and half of these failed to bind Ars. Using this number, we estimate the total number of Ars-specific memory-lineage cells in the spleen to be no more than 50,000 (0.1%) at any one time, and presumably far fewer that are committed to the memory pool. Chromosomal copies of rearranged V genes from single E4+ cells were amplified by nested PCR, and the amplified products were sequenced directly without cloning, using standardized conditions that disclose virtually no Taq polymerase errors. V gene sequence analyses of E4+ cells isolated from single mice confirmed their canonical nature and revealed that they were derived from few precursors. In the average mouse, the E4+ pool was derived from fewer than five canonical precursors. Somatic mutations were found within the V genes of almost all cell isolates. At day 13, a significant fraction of E4+ cells had mutations known to increase antibody affinity for Ars, suggesting they were products of at least one cycle of post-mutational antigen-driven selection. However, the lack of shared mutations by clonally related cells indicated that the selective expansion of mutant subclones typical of memory responses had not yet taken place. This was supported by the observation that half of the E4+ cells failed to bind Ars. Collectively, our results indicate that the memory compartment is a highly selected entity, even at relatively early stages of the primary immune response when somatic mutation and clonal selection are still in progress. If germinal centers are the source of memory B cells, our data suggest that B cell memory may be derived from only a small fraction of all germinal centers.

The Maternal Immune Response to in Utero Hematopoietic Stem Cell Transplantation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 64-64
Author(s):  
Tippi MacKenzie ◽  
Erin Jarvis ◽  
Amar Nijagal ◽  
Tom Le ◽  
Marta Wegorzewska ◽  
...  
Keyword(s):  
Immune Response ◽  
Stem Cell ◽  
Immune System ◽  
B Cells ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
In Utero ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Adaptive Immune

Abstract Abstract 64 In utero hematopoietic stem cell transplantation (IUHSCTx) is a promising treatment strategy for many congenital hematopoietic disorders such as immunodeficiencies. However, clinical applications have been hampered by lack of engraftment, possibly secondary to a host immune response. This has been a conundrum in the field, since the fetus can also be tolerized to allogeneic cells in some circumstances. We hypothesized that it is the maternal immune response which limits engraftment of in utero transplanted cells. Methods: Fetal BALB/c mice at 14 days' gestation were transplanted with age-matched fetal liver (FL) cells (2.5 × 106 cells/fetus) from allogeneic C57B6 mice and levels of circulating donor cell chimerism were determined serially starting at 4 weeks after in utero transplantation. Rates of engraftment (number of chimeric pups/number of surviving pups) and levels of chimerism (donor CD45 cells/total CD45 cells) were compared to controls in which animals were transplanted with congenic cells (C57B6 (CD45.2) fetal hosts transplanted with C57B6 (CD45.1) FL). In order to determine the role of the maternal adaptive immune system, immunodeficient BALB/c.Rag−/− mothers (deficient in T and B cells) were bred to wild type BALB/c males, such that the fetuses (BALB/c.Rag+/−) would be immunocompetent. These fetuses were transplanted with C57B6 FL and rates of engraftment and levels of chimerism in these transplants were compared to those in wild type allogeneic transplants. In order to determine whether the maternal influence is caused by maternal lymphocytes trafficking into the fetus, C57B6 (CD45.2) females were bred to C57B6 (CD45.1) males, such that the fetal cells (CD45.1+/CD45.2+) could be distinguished from maternal cells (CD45.1−/CD45.2+). Fetal blood and tissues were examined for the presence of maternal cells by flow cytometry at various gestational ages. Results: The rate of engraftment after IUHSCTx in control animals transplanted with congenic cells was 14/16 (88%) and average levels of chimerism were 9.9±8.4%. In contrast, the rate of engraftment in wild-type BALB/c fetuses transplanted with allogeneic B6 cells was 11/25 (44%; p<0.05 compared to congenic), and levels of chimerism were 21±19 (p=NS), confirming there is an adaptive immune response to fetal stem cell transplantation. As expected, chimeric animals were tolerant to the donor strain by mixed lymphocyte reaction while injected, non-chimeric animals were sensitized. However, in the absence of a maternal adaptive immune system, rates of chimerism (in immunocompetent BALB/c.Rag+/− pups) increased to 100% (n=10, p<0.05 compared to wild type allogeneic) and levels of chimerism were significantly higher (44±18, p<0.05). Levels of chimerism in engrafted animals declined over time after allogeneic transplantation but not after congenic transplantation, indicating there is a second, late phase immune response to allogeneic cells. However, chimerism levels did not decline in the BALB/c.Rag+/− recipients, suggesting that the maternal immune system has long-lasting effects on the success of fetal transplantation, perhaps by priming the host immune system. In our analysis of maternal/fetal cellular trafficking, we detected maternal lymphocytes in the blood of midgestation fetuses (14±7% at E12.5–E14.5, n=9) which declined gradually and was undetectable after birth. Lineage analysis demonstrated that 45±15 % of maternal cells are Gr-1+ granulocytes and 21±15% are B cells. Trafficking of maternal cells into the fetus was increased following fetal manipulation (injection of PBS < injection of allogeneic HSC). Conclusions: There is an adaptive immune response which limits early engraftment after in utero transplantation of allogeneic cells and leads to a gradual decline in levels of chimerism in engrafted animals. However, in the selective absence of maternal T and B cells, all fetuses transplanted with allogeneic FL cells show long-term, multilineage engraftment and demonstrate donor-specific tolerance. These results indicate that the maternal immune system plays a significant role in the success of fetal HSC transplantation. Cellular trafficking between the mother and fetus may be a mechanism by which maternal lymphocytes encounter cells transplanted into the fetus. Our findings have clinical implications in that the success of IUHSCTx may be improved by harvesting cells from the mother or HLA-matching cells to the mother. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Genetic control of the immune response to staphylococcal nuclease. IV. H-2-linked control of the relative proportions of antibodies produced to different determinants of native nuclease.

1977 ◽  
Vol 145 (1) ◽  
pp. 123-135 ◽  
Author(s):  
J A Berzofsky ◽  
A N Schechter ◽  
G M Shearer ◽  
D H Sachs
Keyword(s):  
Immune Response ◽  
B Cells ◽  
Antibody Response ◽  
Binding Capacity ◽  
Staphylococcal Nuclease ◽  
Gene Control ◽  
Low Responder ◽  
Selection Of ◽  
Ir Genes

The relative proportions of antibodies of different specificities within antisera raised to native staphylococcal nuclease have been studied in several strains of mice in which the antibody response has been shown to be under H-2-linked Ir-gene control. A method was developed in which binding to different radiolabeled fragments of nuclease was titrated against increasing fragment concentration until the binding capacity of the antiserum for that fragment was saturated. In comparing the low responder (H-2b) strain C57BL/10 with its congenic high responder counterpart B10.A (H-2a), it was found that the two strains made markedly and reproducibly different proportions of antibodies to different determinants on native nuclease. Since these two strains differ only at H-2, and therefore have identical immunoglobulin structural gene repertoires, we conclude that H-2-linked Ir genes can control the response to different determinants on the same antigen molecule independently of one another. This result suggests a possible role of H-2-linked genes in the selection of specific B cells.

scholarly journals Immunomodulatory Potential of Diuretics

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1315
Author(s):  
Paweł Bryniarski ◽  
Katarzyna Nazimek ◽  
Janusz Marcinkiewicz
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Experimental Conditions ◽  
Geriatric Population ◽  
Serious Infections ◽  
Strongly Connected ◽  
Anti Inflammatory ◽  
Immunomodulatory Potential ◽  
Selection Of ◽  
Inflammatory Effect

In this review, diuretics and their immunomodulatory functions are described. The effects on the immune response of this group of drugs are reported in patients suffering from hypertension and under experimental conditions involving animal models and cell line studies. The pathogenesis of hypertension is strongly connected to chronic inflammation. The vast majority of diuretics modulate the immune response, changing it in favor of the anti-inflammatory response, but depending on the drug, these effects may differ. This topic is significantly important in medical practice regarding the treatment of patients who have coexisting diseases with chronic inflammatory pathogenesis, including hypertension or chronic heart failure. In patients with metabolic syndrome, allergies, or autoimmune disorders, the anti-inflammatory effect is favorable, because of the overstimulation of their immune system. Otherwise, in the geriatric population, it is important to find the proper anti- and pro-inflammatory balance to avoid an enhancement of immune response suppression, which can result in reducing the risk of serious infections that can occur due to the age-diminished function of the immune system. This article is intended to facilitate the selection of an antihypertensive drug that depends on the patient’s immune situation.

scholarly journals PD−L1 immunostaining: what pathologists need to know

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Mohammed Akhtar ◽  
Sameera Rashid ◽  
Issam A. Al-Bozom
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Immune Cells ◽  
Immune Checkpoint ◽  
Immunohistochemical Staining ◽  
Vital Role ◽  
Checkpoint Proteins ◽  
Immune Checkpoint Proteins ◽  
Selection Of Patients ◽  
Selection Of

Abstract Background Immune checkpoint proteins, especially PD-L1 and PD-1, play a crucial role in controlling the intensity and duration of the immune response, thus preventing the development of autoimmunity. These proteins play a vital role in enabling cancer cells to escape immunity, proliferate and progress. Methods This brief review highlights essential points related to testing for immune checkpoint therapy that histopathologists need to know. Results In recent years, several inhibitors of these proteins have been used to reactivate the immune system to fight cancer. Selection of patients for such therapy requires demonstration of PD-L1 activation on the tumor cells, best done by immunohistochemical staining of the tumor and immune cells using various antibodies with predetermined thresholds. Conclusions Immune checkpoint therapy appears to be promising and is rapidly expanding to include a large variety of cancers.

Biased immunoglobulin variable region gene expression by Ly-1 B cells due to clonal selection

1989 ◽  
Vol 19 (7) ◽  
pp. 1289-1295 ◽  
Author(s):  
Christopher A. Pennell ◽  
Thomas J. Mercolino ◽  
Therese A. Grdina ◽  
Larry W. Arnold ◽  
Geoffrey Haughton ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cells ◽  
Clonal Selection ◽  
Variable Region ◽  
Region Gene ◽  
Immunoglobulin Variable Region ◽  
Variable Region Gene ◽  
Immunoglobulin Variable Region Gene

scholarly journals In Situ Studies of the Primary Immune Response to (4-Hydroxy-3-Nitrophenyl)Acetyl. V. Affinity Maturation Develops in Two Stages of Clonal Selection

1998 ◽  
Vol 187 (6) ◽  
pp. 885-895 ◽  
Author(s):  
Yoshimasa Takahashi ◽  
Pinaki R. Dutta ◽  
Douglas M. Cerasoli ◽  
Garnett Kelsoe
Keyword(s):  
Immune Response ◽  
Clonal Selection ◽  
Cd40 Ligand ◽  
Primary Response ◽  
Affinity Maturation ◽  
Primary Immune Response ◽  
Cellular Interactions ◽  
Serum Antibodies ◽  
High Affinity ◽  
Selection Of

To examine the role of germinal centers (GCs) in the generation and selection of high affinity antibody-forming cells (AFCs), we have analyzed the average affinity of (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific AFCs and serum antibodies both during and after the GC phase of the immune response. In addition, the genetics of NP-binding AFCs were followed to monitor the generation and selection of high affinity AFCs at the clonal level. NP-binding AFCs gradually accumulate in bone marrow (BM) after immunization and BM becomes the predominant locale of specific AFCs in the late primary response. Although the average affinity of NP-specific BM AFCs rapidly increased while GCs were present (GC phase), the affinity of both BM AFCs and serum antibodies continued to increase even after GCs waned (post-GC phase). Affinity maturation in the post-GC phase was also reflected in a shift in the distribution of somatic mutations as well as in the CDR3 sequences of BM AFC antibody heavy chain genes. Disruption of GCs by injection of antibody specific for CD154 (CD40 ligand) decreased the average affinity of subsequent BM AFCs, suggesting that GCs generate the precursors of high affinity BM AFCs; inhibition of CD154-dependent cellular interactions after the GC reaction was complete had no effect on high affinity BM AFCs. Interestingly, limited affinity maturation in the BM AFC compartment still occurs during the late primary response even after treatment with anti-CD154 antibody. Thus, GCs are necessary for the generation of high affinity AFC precursors but are not the only sites for the affinity-driven clonal selection responsible for the maturation of humoral immune responses.

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