Disease relevance of Ighg1

• In the nude mice experiment, only the IgG2a variant inhibited growth of human colorectal carcinoma, while IgG1 and IgG2b were ineffective [1].
• As has been shown with conventional antibodies, monoclonal IgG1 and IgE are the two classes capable of sensitizing the mouse for anaphylactic reactions, IgE sensitizes the rat, and IgG2a sensitizes the guinea pig [2].
• Small amounts of membrane gamma mRNAs persist in plasmacytomas secreting IgG1, IgG2a, or IgG2b, suggesting that competition between alternative RNA processing pathways governs the synthesis of membrane and secretory gamma chain mRNAs [3].
• Peritoneal mast cells, bone marrow-derived mast cells (BMMC), and the mastocytoma cells P815 were found to bear trypsin-resistant, 2.4G2+, low-affinity receptors binding mouse monoclonal IgG1, IgG2a, and IgG2b, i.e., Fc gamma RII [4].
• SCID mice were found to have rapid blood clearance of injected mouse IgG2a antibodies (Ab), while IgG1 Ab were cleared normally [5].

High impact information on Ighg1

• The extent of segmental flexibility in times of nanoseconds and the capacity to fix complement were greatest for IgG2b, intermediate for IgG2a, and least for IgG1 and IgE [6].
• Here, we demonstrate that mice deficient for the ligand-binding alpha chain of Fc gamma RIII lack NK cell-mediated antibody-dependent cytotoxicity and phagocytosis of IgG1-coated particles by macrophages [7].
• In addition, the transgenes lacking the 3' end of the locus express reduced amounts of gamma1 germline transcripts and 2-3% of the amount of Tg IgG1 in tissue culture compared with intact transgenes [8].
• In contrast, erythrocyte-binding affinities only played a minor role in in vivo hemolytic activities of the IgG1 and IgG2a isotypes of 34-3C and 4C8 antibodies, where complement was not or only partially involved, respectively [9].
• Passive administration of an IgG1 mAb protects FcRgamma+/- mice infected with C. neoformans, but fails to protect FcRgamma-/- mice, indicating that the gamma chain acting through FcgammaRI and/or III is essential for IgG1-mediated protection [10].

Chemical compound and disease context of Ighg1

• Immunoglobulin G1 (IgG1), IgG2a, and IgG2b switch variants were derived from an IgG3 monoclonal antibody directed against the VP3 envelope glycoprotein of lactate dehydrogenase-elevating virus (LDV) [11].
• Monoclonal antibodies (MABs) were produced against an ethylenediaminetetraacetate (EDTA) extract of Leptospira interrogans serovar icterohaemorrhagiae being characterized by gel precipitation as IgM and IgG (IgG1 and IgG2b) [12].
• This response was associated with increased allergen-specific IgE and IgG1 production, increased levels of interleukin-4 and interleukin-5 in bronchoalveolar lavage fluid and eosinophilic lung inflammation [13].

Biological context of Ighg1

• In laboratory mouse strains RFLP proved to be more sensitive in the detection of Igh-4 (C gamma 1) alleles than serological methods [14].
• The nucleotide sequences of the exons encoding membrane-bound IgG1, IgG2a, and IgG2b of mouse were determined and compared with the sequence of membrane-bound IgM [15].
• Whereas IgG2a induced ADCC to the same extent in monocytes from all donors, IgG1 showed a heterogeneous pattern, which corresponded to the heterogeneity in T cell proliferation studies [16].
• Defective Fc gamma RII gene expression in macrophages of NOD mice: genetic linkage with up-regulation of IgG1 and IgG2b in serum [17].
• The dissociation kinetics of IgG1 decreased considerably in a low ionic strength buffer, indicating that the IgG1-moFc gamma RII interaction has significant electrostatic components [18].

Anatomical context of Ighg1

• Mouse macrophages have two FcRs-FcRI, which is trypsin-sensitive and binds IgG2a, and FcRII, which is trypsin-resistant and binds IgG2b and IgG1 complexes [19].
• IgG1 CD20 mAbs induced B cell depletion through preferential, if not exclusive, interactions with low-affinity FcgammaRIII [20].
• The 34-3C autoantibody opsonizing extensively circulating erythrocytes efficiently activated complement in vivo (IgG2a = IgG2b > IgG3), except for the IgG1 isotype, while the 4C8 IgG autoantibody failed to activate complement [9].
• Three different monoclonal antibody isotypes, IgG1, IgG2b, and IgG2a, were derived by selection of isotype-switch variants from the CO-19-9 hybridoma [1].
• Analysis of the binding of three isotypes to the human FcR expressed by U937 cells induced by gamma interferon has shown that only IgG2a proteins bound to high-affinity FcR, but not IgG1 or IgG2b variants [1].

Associations of Ighg1 with chemical compounds

• The predominant serum IgG subclass response to O139 lipopolysaccharide was initially IgG3 until day 56, after which IgG1 was predominant [21].
• When preformed complexes were added to serum, those containing IgG2 or IgM were potent activators of C4, whilst IgG1 complexes were less efficient [22].
• C3 activation in normal serum was similar for complexes containing IgG1, IgG2a, IgG2b or IgM [22].
• Intact antibodies (mouse monoclonal antibodies [MoAbs] IgG1 and IgG2b, human immune heat-inactivated serum [predominantly IgG1], and IgG purified from human immune serum) that block the sialic acid-binding site on HA significantly reduced (> 80%) neutrophil adherence to influenza-infected epithelial cells [23].
• Capsule-specific IgG1 and IgG2 Abs are induced upon vaccination with polysaccharide-based vaccines that mediate host protection [24].

Physical interactions of Ighg1

• This conclusion is supported by the observation that after proteolysis, the Fc gamma RII-mediated binding of EA-mouse IgG1 becomes susceptible to inhibition by (monomeric) human IgG [25].
• Incubation of neutrophils with a mAb against the FcRIII completely blocked the binding of IgG1 complexes and IgG3 complexes [26].
• The COOH terminus of the IgG2 CH2 domain was found to contain accessory site(s) since it enhanced the binding properties of both IgG1 PLLGG and native IgG1 [27].

Regulatory relationships of Ighg1

• These adjuvants not only enhanced the amount of IgG evoked but also shifted the IgG subclass distribution from mainly IgG1 toward the complement-activating subclasses IgG2a and IgG2b [28].
• In contrast, absence of the inhibiting FcgammaRIIB augmented the Hg-induced increase of both serum IgG1 and IgE [29].

Other interactions of Ighg1

• We found new allotypes of the Igh-1 and Igh-4 loci [30].
• It is reported here that rat IgG1 antibodies, which are associated in the rat with a Th1-type response, act as highly effective blocking antibodies over a wide concentration range [31].
• Mouse immunoglobulin epsilon chain gene was cloned from DNA of a hybridoma producing anti-dinitrophenyl IgE, which was constructed by fusing a spleen cell of a BALB/c mouse with a variant clone of MOPC21 myeloma (IgG1 producer) [32].
• For example, two independently produced IgG1 monoclonal reagents raised against the Igh-1b allotype were poorly suppressive or nonsuppressive, whereas an IgG3 and an IgG2a monoclonal antibody induced a 90% suppression of the target allotype in transferred adult SC [33].
• Probably as a consequence of this reduction in mature B cells, Bob1-deficient mice show reduced serum titers of the immunoglobulin isotypes IgG1, IgG2a, IgG2b and IgA, but not IgM [34].

Analytical, diagnostic and therapeutic context of Ighg1

• We also found an increase in total protein (TP) level and IL-5 production in bronchoalveolar lavage (BAL) fluid and an increase in SRW-specific Th2-type immunoglobulins (IgG1, IgG2b) and total serum IgE levels [35].
• The segmental flexibility and complement fixation activity were measured of six genetically engineered molecules (the four human IgG isotypes, mouse IgG3 and rabbit IgG) and the remaining three mouse IgG isotypes, (IgG1, IgG2a and IgG2b), isolated previously by somatic cell genetic techniques [36].
• In flow cytometry, there was weak reactivity with granulocytes, a reactivity also observed with two previously described highly specific Le(y) mouse mAbs--BR55-2 (IgG3) and B3 (IgG1) [37].
• Thus, 7S IgG1, 7S IgG2, 7S IgG2a, and 7S IgG2b were obtained which were completely pure by criteria of immunodiffusion and immunoelectrophoresis [38].
• Stable F(ab')2 can be produced in good yield from IgG1 with pepsin at pH 3.5 to 4.0 and can be made directly by pepsin treatment of ascites fluids or cell culture supernatants containing IgG1 [39].

References