IgG Antibody Classes Research Articles

Challenges of laboratory diagnosis of Lyme disease ‒ Questionnaire survey results.

The accuracy in diagnostic testing for Lyme disease in the early stages of infection is an important factor necessary for delivering proper treatment to patients. Atotal of 173 individuals with confirmed Lyme disease or with laboratory testing underway participated in the quantitative survey. ELISA was the first test conducted in 51% of the respondents, 28% of whom yielded positive findings of both IgM and IgG antibody classes. The positivity of ELISA test findings was confirmed by Western blot in 100% of results. Negative results of ELISA were consistent with Western blot only in less than half of the patients. More than half of the respondents had not been tested for any bacterial or viral co-infections. The results of serological testing were not consistent with clinical findings in all cases, including those with clinically discernible skin manifestation of erythema migrans. The comparison of results obtained by ELISA and Western blot revealed significant discrepancies. Simultaneous infections by vectors with several pathogens were detected (Tab. 3, Fig. 2, Ref.15).

Platelet-localized ST6Gal1 does not impact IgG sialylation.

The IgG antibody class forms an important basis of the humoral immune response, conferring reciprocal protection from both pathogens and autoimmunity. IgG function is determined by the IgG subclass, as defined by the heavy chain, as well as the glycan composition at N297, the conserved site of N-glycosylation within the Fc domain. For example, lack of core fucose promotes increased antibody-dependent cellular cytotoxicity, whereas α2,6-linked sialylation by the enzyme ST6Gal1 helps to drive immune quiescence. Despite the immunological significance of these carbohydrates, little is known about how IgG glycan composition is regulated. We previously reported that mice with ST6Gal1-deficient B cells have unaltered IgG sialylation. Likewise, ST6Gal1 released into the plasma by hepatocytes does not significantly impact overall IgG sialylation. Since IgG and ST6Gal1 have independently been shown to exist in platelet granules, it was possible that platelet granules could serve as a B cell-extrinsic site for IgG sialylation. To address this hypothesis, we used a platelet factor 4 (Pf4)-Cre mouse to delete ST6Gal1 in megakaryocytes and platelets alone or in combination with an albumin-Cre mouse to also remove it from hepatocytes and the plasma. The resulting mouse strains were viable and had no overt pathological phenotype. We also found that despite targeted ablation of ST6Gal1, no change in IgG sialylation was apparent. Together with our prior findings, we can conclude that in mice, neither B cells, the plasma, nor platelets have a substantial role in homeostatic IgG sialylation.

Sensitivity of some Immunoglobulin G class and subclass antibodies to adult <i>Onchocerca volvulus</i> SDS-extracted antigens.

Indirect sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure serum antibody responses in onchocerciasis patients. Apparently, IgG antibody class was more sensitive than IgG1, IgG3 and IgG4 responses to Onchocerca volvulus adult worms sodium duodecyl sulphate (SDS) extracted crude antigens in proven clinical and parasitological cases (n=95). Sensitivity varied slightly among the IgG1, IgG3 and IgG4 isotypes. All cases were positive for IgG, with 98%, 97% and 96% for the IgG isotypes respectively. Those with evidences of palpable nodule and skin microfilariae (n=32) were all seropositive (100%) for the three IgG isotypes-assays. A decrease in seropositivity was recorded among the assumed endemic normals or those with no evidence of infection (n=19), yet IgG recorded the highest with 90% and IgG4 was the least with 58%. It is concluded that the IgG1 and IgG3 assays have great potential as a screening test, while IgG4 could serve as a confirmatory test. These assays could be useful in detecting cases elusive to parasitological and clinical prognosis particularly in post-control surveillance situations. Keywords: Onchocerca volvulus, Serology, sensitivity, Screening, Diagnosis, Antigens and Antibodies.

Isotype specific immune responses in murine experimental toxocariasis.

In this work, a murine experimental model of toxocariasis has been developed in BALB/c, C57BL/10 and C3H murine strains orally inoculated with 4,000 Toxocara canis embryonated eggs, in order to investigate the isotype-specific immune responses against excretory-secretory antigens from larvae. T. canis specific IgG+M, IgM, IgG, IgA, IgG1, IgG2a and IgG3 were tested by ELISA. The dynamics of the specific immunoglobulins (IgG+IgM) production showed a contrasting profile regarding the murine strain. Conversely to the results obtained with the IgM isotype, the IgG antibody class showed similar patterns to those obtained with IgG+IgM antibodies, only in the case of the BALB/c strain, being different and much higher than the obtained with IgG+IgM antibodies, when the C3H murine strain was used. The antibodies IgG+IgM tested in BALB/c and C57BL/10 were both of the IgM and IgG isotypes. Conversely, in the C3H strain only IgG specific antibody levels were detected. The IgG1 subclass responses showed a similar profile in the three murine strains studied, with high values in BALB/c, as in the case of the IgG responses.

Humoral immune responses induced by Gymnorhynchus gigas extracts in BALB/c mice

The aim of this study was to determine if the plerocercoid larvae of Gymnorhynchus gigas, a common cestode of the ray's bream (Brama raii), possess antigenic compounds potentially capable of provoking anaphylactic episodes. A murine experimental model, using BALB/c mice, was developed to study the humoral immune response induced by G. gigas extracts. A highly specific humoral immune response was detected and cross-reactions were not observed between parasite and host antigens. The presence of IgM and IgG3 levels suggest the presence of thymus-independent antigens in the parasitic extract. The IgG antibody class showed the highest levels, with the IgG1 the predominant subclass. These IgG1 levels are in accordance with the supposed presence of a type I allergic reaction after the ingestion of G. gigas plerocercoids parasitizing fish, as well as inducing anaphylaxia in fish. These results indicate that somatic products released from ingested larvae of G. gigas could induce the development of a Th2 response capable of causing allergic disorders.

Humoral immune responses induced by Gymnorhynchus gigas extracts in BALB/c mice

The aim of this study was to determine if the plerocercoid larvae of Gymnorhynchus gigas, a common cestode of the ray’s bream (Brama raii), possess antigenic compounds potentially capable of provoking anaphylactic episodes. A murine experimental model, using BALB/c mice, was developed to study the humoral immune response induced by G. gigas extracts. A highly specific humoral immune response was detected and cross-reactions were not observed between parasite and host antigens. The presence of IgM and IgG3 levels suggest the presence of thymus-independent antigens in the parasitic extract. The IgG antibody class showed the highest levels, with the IgG1 the predominant subclass. These IgG1 levels are in accordance with the supposed presence of a type I allergic reaction after the ingestion of G. gigas plerocercoids parasitizing fish, as well as inducing anaphylaxia in fish. These results indicate that somatic products released from ingested larvae of G. gigas could induce the development of a Th2 response capable of causing allergic disorders.

Aspergillus fumigatus-specific antibodies in allergic bronchopulmonary aspergillosis and aspergilloma: evidence for a polyclonal antibody response

Patients with the Aspergillus-induced diseases allergic bronchopulmonary aspergillosis (ABPA), aspergilloma (fungus ball), and Aspergillus skin test-positive asthma were differentiated immunologically by radioimmunoassay based on their total immunoglobulin E (IgE) and Aspergillus fumigatus-specific IgE levels. In this study, a new, highly sensitive biotin-avidin-linked immunosorbent assay was used to evaluate A. fumigatus-specific antibodies of all immunoglobulin classes. Studied populations included 13 patients with ABPA, 12 with aspergilloma, 9 with Aspergillus skin test-positive asthma, and 9 normal individuals without asthma. A. fumigatus-specific antibodies of all classes were elevated in patients with ABPA, variably elevated in those with aspergilloma, and lowest in the other two groups. This assay demonstrated significantly higher specific IgE antibody levels in the ABPA group over those of the other groups, even with 1:1,000 dilutions of the sera. This study demonstrated that ABPA is a disease characterized by a polyclonal antibody response to Aspergillus antigen and not just a response to IgE and IgG antibody classes. The measurement of other antibody classes, particularly IgD and IgA, could enhance the immunodiagnosis of ABPA. The biotin-avidin-linked immunosorbent assay was found to be a highly sensitive assay that can be a clinically useful alternative to radioimmunoassay in the measurement of A. fumigatus-specific antibodies.

Cell Interactions Between Histoincompatible T and B Lymphocytes

Abstract Two possible explanations for the failure of primed histoincompatible T and B lymphocytes to cooperate in secondary responses of the IgG antibody class have been investigated in the present study: 1) The possible existence of subtle suppressive mechanisms developing as a consequence of mixing two histoincompatible cell populations; and 2) The possible inability of histoincompatible carrierprimed T cells to recognize and/or be induced to function by carrier determinants presented to them in association with foreign MHC antigens (i.e., the “altered-self” recognition hypothesis). Absence of suppression has been verified by two different approaches, including: 1) the failure of histoincompatible T cells, even in great excess, to interfere with physiologic cooperation between syngeneic T and B lymphocytes; and 2) the failure of histoincompatible B cells to interfere with physiologic cooperation between semi-syngeneic F1 hybrid T cells and parental B cells. The unlikelihood of the “altered-self” explanation for failure of histoincompatible T and B cells to cooperate has been indicated by an inability to circumvent the requirement for I-region identity by priming T cells with allogeneic macrophagebound antigen even when the latter cells are of identical haploytpe with the allogeneic B cells employed in the final cooperation assay. These results strongly substantiate the existence of true genetic restrictions in T-B cell intractions in secondary responses to hapten-protein conjugates. The validity of other observations indicating an absence of genetic restrictions in certain circumstances, considered in the context of our own data, has suggested the possibility that virgin T and B lymphocytes reciprocally influence one another during the course of cell interactions in response to antigenic and/or other signals, a process we term “adaptive differentiation.”

Induction of immunological tolerance in immunoglobulin E B lymphocytes in rats

Immunological tolerance has been, induced in 2,4-dinitrophenyl (DNP)-specific bone marrow-derived or B lymphocytes of the IgE and IgG antibody classes by treatment of rats with the DNP derivative of the D-amino acid copolymer, D-glutamic acid, D-lysine (D-GL). The tolerant state is manifested as an inability of treated rats to produce serum anti-DNP antibodies and the failure of peritoneal cells from tolerant animals to release histamine following in vitro antigen challenge. The implications of these and related observations for potential therapeutic measures in clinical hypersensitivity states are discussed.

HAPTEN-SPECIFIC IgE ANTIBODY RESPONSES IN MICE

The present studies have established conditions for the demonstration of cooperative interactions between specific T and B lymphocyte populations in the development of IgE antibody responses in vivo in mice. This has been accomplished by utilizing a system which permits the successful adoptive transfer to irradiated recipients of DNP-specific secondary IgE responses with spleen cells from suitably primed syngeneic donor mice. Thus, adoptively transferred DNP-KLH or DNP-ASC-primed spleen cells produced high levels of anti-DNP antibodies of both IgE and IgG antibody classes in response to challenge with the appropriate homologous priming conjugate but failed to develop more than meager responses to the reciprocal heterologous conjugate. However, when spleen cells from donors primed to the second carrier were concomitantly transferred with hapten-primed lymphocytes, secondary IgE ant-DNP responses were consistently obtained upon challenge with the heterologous conjugate. Moreover, we have been able to elicit augmented primary IgE anti-DNP antibody responses to either DNP-ASC or DNP-KLH after adoptive transfer of spleen cells from donors primed only to the carrier, ASC or KLH, respectively. This adoptive transfer system has enabled us to provide direct proof for the participation of theta-bearing T lymphocytes in antibody responses of the IgE class. Thus, the capacity of ASC-primed spleen cells to effectively cooperate with the DNP-KLH-primed lymphocytes in the adoptive secondary response to DNP-ASC could be abolished by in vitro treatment of such cells with anti-theta serum plus complement. This was true not only for the anti-DNP response of the IgG antibody class, but for the IgE antibody class as well. These studies have, furthermore, demonstrated the capacity to stimulate secondary anti-DNP antibody production in vivo by the concomitant administration of the DNP and relevant carrier determinants on separate molecules. This was more readily seen in the IgE than in the IgG antibody class. Thus, DNP-ASC-primed cells developed significant IgE, but more variable IgG, anti-DNP responses upon challenge with DNP-KLH plus unconjugated ASC. Antibody responses of both classes elicited in this manner were appreciably improved by the transfer of additional carrier (ASC)-primed cells. These and other results presented herein suggest that IgE B lymphocyte precursors may be inherently more sensitive than IgG B cells to at least certain of the functions of T lymphocytes concerned with regulatory mechanisms involved in antibody production.

Hapten-specific IgE antibody responses in mice. I. Secondary IgE responses in irradiated recipients of syngeneic primed spleen cells.

The present studies have established conditions for the demonstration of cooperative interactions between specific T and B lymphocyte populations in the development of IgE antibody responses in vivo in mice. This has been accomplished by utilizing a system which permits the successful adoptive transfer to irradiated recipients of DNP-specific secondary IgE responses with spleen cells from suitably primed syngeneic donor mice. Thus, adoptively transferred DNP-KLH or DNP-ASC-primed spleen cells produced high levels of anti-DNP antibodies of both IgE and IgG antibody classes in response to challenge with the appropriate homologous priming conjugate but failed to develop more than meager responses to the reciprocal heterologous conjugate. However, when spleen cells from donors primed to the second carrier were concomitantly transferred with hapten-primed lymphocytes, secondary IgE ant-DNP responses were consistently obtained upon challenge with the heterologous conjugate. Moreover, we have been able to elicit augmented primary IgE anti-DNP antibody responses to either DNP-ASC or DNP-KLH after adoptive transfer of spleen cells from donors primed only to the carrier, ASC or KLH, respectively. This adoptive transfer system has enabled us to provide direct proof for the participation of θ-bearing T lymphocytes in antibody responses of the IgE class. Thus, the capacity of ASC-primed spleen cells to effectively cooperate with the DNP-KLH-primed lymphocytes in the adoptive secondary response to DNP-ASC could be abolished by in vitro treatment of such cells with anti-θ serum plus complement. This was true not only for the anti-DNP response of the IgG antibody class, but for the IgE antibody class as well. These studies have, furthermore, demonstrated the capacity to stimulate secondary anti-DNP antibody production in vivo by the concomitant administration of the DNP and relevant carrier determinants on separate molecules. This was more readily seen in the IgE than in the IgG antibody class. Thus, DNP-ASC-primed cells developed significant IgE, but more variable IgG, anti-DNP responses upon challenge with DNP-KLH plus unconjugated ASC. Antibody responses of both classes elicited in this manner were appreciably improved by the transfer of additional carrier (ASC)-primed cells. These and other results presented herein suggest that IgE B lymphocyte precursors may be inherently more sensitive than IgG B cells to at least certain of the functions of T lymphocytes concerned with regulatory mechanisms involved in antibody production.