Appearance Of IgG Research Articles

Structure and expression of human IgG FcRII(CD32). Functional heterogeneity is encoded by the alternatively spliced products of multiple genes.

The structural heterogeneity of the human low affinity receptor for IgG, FcRII(CD32), has been elucidated through the isolation, characterization, and expression of cDNA clones derived from myeloid and lymphoid RNA. These clones predict amino acid sequences consistent with integral membrane glycoproteins with single membrane spanning domains. The extracellular domains display sequence homology to other Fc gamma Rs and members of the Ig supergene family. A minimum of three genes (Fc gamma RIIa, IIa', and Fc gamma RIIb) encode these transcripts, which demonstrate highly related extracellular and membrane spanning domains. IIa/IIa' differ substantially in the intracytoplasmic domain from IIb. Alternative splicing of the IIb gene generates further heterogeneity in both NH2- and COOH-terminal domains of the predicted proteins. Comparison to the murine homologues of these molecules reveals a high degree of conservation between the products of one of these genes, Fc gamma RIIb, and the murine beta gene in primary sequence, splicing pattern, and tissue distribution. In contrast, the sequence of IIa' indicates its relationship to the beta-like genes, with mutation giving rise to a novel cytoplasmic domain, while IIa is a chimera of both alpha- and beta-like genes. Expression of these cDNA molecules by transfection results in the appearance of IgG binding molecules that bear the epitopes defined by the FcRII(CD32) mAbs previously described.

Antibody production by the pig colon during infection with Treponema hyodysenteriae

When 47 pigs were dosed orally with cultures of Treponema hyodysenteriae, 44 (94 per cent) developed swine dysentery. Of those which recovered and were rechallenged, nine of 21 (43 per cent) showed clinical signs, as did one of 10 (10 per cent) challenged on a third occasion. Clinical disease was associated with development of specific IgG, IgA and IgM antibodies in serum and the local production of IgA in gut mucosal tissues. The appearance of antibody was not directly related to protection but rather indicated either prolonged exposure (in the case of serum IgG) or recent exposure to T hyodysenteriae (for secretory IgA). Infection also resulted in the appearance of IgG and IgA memory cells in gut-associated lymphoid tissue. However, these studies indicated that humoral immunity alone is not responsible for the onset of a protective response to T hyodysenteriae in the colon.

Chlamydial Salpingitis in Female Guinea Pigs Receiving Oral Contraceptives

Female guinea pigs were given daily doses of a combination of oral contraceptive (OC) agents, consisting of mestranol and norethynodrel suspended in sesame oil or distilled H2O, and were infected in the genital tract with the chlamydial agent of guinea pig inclusion conjunctivitis (GPIC). Counts of chlamydial inclusions in cells of vaginal smears collected during infection, showed prolongation and enhancement of infection in OC-treated animals as compared with controls. Appearance of IgG and IgA antibodies to GPIC in genital secretions, as determined by enzyme-linked immunosorbent assay (ELISA), was also delayed in OC-treated animals as compared with controls. OC-treated infected animals were killed on days 15 and 43, and gross pathological evidence for ascending infection culminating in salpingitis was found in all of five and four of five animals, respectively. On the other hand, among untreated infected controls on each sacrifice day, only one of five animals had any evidence for ascending infection. Chlamydiae were detected by light and electron microscopy in fallopian tube tissue collected on day 15 following OC-treatment but not in tissue from control animals.

Keyhole limpet hemocyanin-propagated Peyer's patch T cell clones that help IgA responses.

Four T cell clones, isolated from Peyer's patches of keyhole limpet hemocyanin (KLH)-primed BALB/c mice, were selected on the basis of their ability to help IgA responses by TNP-KLH-primed BALB/c mouse B cells. Two were KLH-dependent both in terms of their own proliferative response and in terms of their help for that of B cells. The other two were autoreactive and helped B cells proliferate independently of the presence of Ag. Both primed and unprimed B cells proliferated to some extent when helped by the KLH-reactive clones in the presence of high concentrations of either KLH or TNP-KLH. Much higher proliferation was, however, induced when primed, but not unprimed, B cells were exposed to the T cells in the presence of low concentrations of TNP-KLH but not KLH, i.e., under conditions favoring direct, cognate interaction between the T and B cells. Only modest IgM, and no IgG or IgA plaque-forming cell (PFC) responses were generated by TNP-primed B cells upon interaction with either autoreactive T cells in the absence of Ag or KLH-reactive T cells in the presence of high concentrations of KLH. For high IgM responses as well as for the appearance of IgG and IgA PFC responses, TNP-KLH was required whatever the source of the T cell help. The isotype ratios depended on the TNP-KLH concentration; IgA responses were highest and IgM responses lowest at the lowest TNP-KLH concentrations suggesting that the precursors of the IgA PFC have higher average affinity for TNP than the precursors of IgM PFC. Overall, the results are compatible with the idea that the precursors of IgA and IgG PFC and many of the precursors of IgM PFC in the long term primed B cell populations used in these experiments require engagement of their Ag-receptors before they express sufficient class II Ag and/or receptors for "switch" and differentiation factors for cognate interaction with T cells leading to PFC responses.

Induction of salivary antibody responses in rats after immunization in Peyer's patches.

We examined salivary, milk, and serum antibody levels after immunization in the Peyer's patches (Pp) of rats with horse spleen ferritin. Priming of the Pp one day after parturition led to the appearance of IgG, but not IgA or IgM, anti-ferritin antibodies in saliva 9 days later. IgG and IgM antibodies were detected both in milk and in serum, whereas IgA antibodies could only be demonstrated in milk. During a second lactation period the salivary antibodies had vanished but IgG antibodies could still be detected in milk and serum. During a third lactation period, when the rats were immunized in the Pp a second time, not only IgG but also IgA anti-ferritin antibodies appeared in the saliva. Salivary IgG antibody levels and milk IgG, IgM, and IgA antibody levels were higher than those observed after primary immunization in the Pp. The IgG antibody activity in the saliva was positively correlated to the serum IgG antibody activity. It is concluded that salivary IgA antibody responses can be induced by immunization in the Pp. The results of this study suggests that IgA antibodies detected in saliva are produced locally by cells that have migrated from the intestinal lymphoid tissue to the salivary glands.

Release of antigens and allergens during shake‐culture of Aspergillus fumigatus

The appearance of IgG and IgE binding components in the medium of shake cultures of Aspergillus fumigatus has been studied. Cultures were grown in synthetic asparagine medium at 35 degrees C and flasks harvested in duplicate 1, 2, 3, 4, 7 and 14 days after inoculation. The pH of the medium dropped from its initial value of 5.5 to pH 3, and then after 4 days gradually increased up to pH 7.5 in the 14-day medium. The weight of mycelium, after an initial peak followed by a slight decline, increased as the pH of the medium increased. Components able to bind IgG and IgE from pooled ABPA sera were detected by crossed immunoelectrophoresis/self-crossed radioimmunoelectrophoresis within 24 h of growth, but maximal release of both antigens and allergens coincided with the increase in pH of the medium and was seen in the 14-day culture filtrate. Two recognised "major" antigens, Ag 7 and Ag 13, detected using the relevant monospecific antisera, were present in the culture medium after 14 days of growth and similarly for Ag 3, the major allergen, although another allergen, Ag 1, was identified in the 1-day extract. None of the culture filtrates was found to contain the "C-substance" polysaccharide.

The antibody response to bovine lymphocyte alloantigens

Antibodies were raised against lymphocyte cell-surface antigens by multiple immunisations with purified lymphocytes or by the exchange of skin allografts. Eighteen of 21 cattle immunised with lymphocytes raised a detectable cytotoxic antibody response. The serum antibody from 10 responders recognized only common lymphocyte antigens, those antigens which are present on all peripheral blood lymphocytes. One animal responded only to B lymphocyte antigens while 7 others responded to both classes of antigens. The amount of antibody produced varied greatly between individuals; antibody titres ranged from 1 to 1028. Antibody raised early in the response was sensitive to treatment with 2-mercaptoethanol (2-ME) suggesting that IgM was the predominant class of immunoglobulin. Subsequently antibody became resistant to this treatment suggesting the appearance of IgG. The antibody responses following the exchange of skin grafts were very similar in all 12 cattle studied. High titred antibody to common lymphocyte antigens was detected in the serum 14 days after grafting. The early antibody activity was sensitive to 2-ME treatment but became totally resistant within 14 days. Total peak antibody titres ranged from 128–2048. Antibody to B lymphocyte antigens was identified in 8 of the 12 cattle. The responses to B lymphocyte antigens were similar to those against the more widely distributed common lymphocyte antigens with respect to time of antibody appearance, time of peak titre and sensitivity to 2-ME. Peak titres ranged from 2 to 32. The change in antibody specificity with time was also studied. Sera from 11 of the 18 cattle which had responded against lymphocytes showed an increase or broadening in reaction frequency as immunisations increased, suggesting the production of antibody to secondary specificities. In the cattle which had been skin grafted, the broadest reaction patterns were seen 14 to 21 days after grafting. The broadest reaction patterns were seen when the antibody responses were at their highest titre levels and narrowed as titres decreased.

Oral—parenteral immunization leads to the appearance of IgG auto-anti-idiotypic cells in mucosal tissues

The appearance of plasma cells, specific for antigen or autologous idiotypic antibody, in rabbits immunized systemically, orally, or orally-systemically was determined using immunofluorescence techniques. Oral or parenteral immunizations alone did not lead to the appearance of anti-idiotypic cells in mucosal tissues, although IgA antigen-binding cells were observed in these sites after the oral administration of antigen. However, when rabbits were primed with orally administered antigen, followed by a regimen of concurrent oral—parenteral immunizations, IgG anti-idiotypic plasma cells were demonstrated in mucosal lymphoid tissues.

Investigation of some factors which influence the absorption of IgG by the neonatal piglet

The absorption by the neonatal gut of purified swine IgG isolated from maternal serum was studied in 91 motherless piglets raised without swine colostrum, to investigate some of the factors which influence absorption. Factors studied included the amount of IgG administered, the effect of bovine colostrum fed concurrently, the influence of starvation and the effect of lactose. Administration of iodinated IgG within 3 hours after birth resulted in the appearance of IgG in the piglet circulation in unaltered form. Immediate feeding of bovine colostrum followed by administration of iodinated IgG at 72 hours resulted in the appearance of only IgG digestion fragments in the circulation. Administration of 15 g of lactose during the first 24 hours reduced absorption of IgG by 26% compared to controls while treatment with 54 g of lactose reduced absorption by 94%. On the contrary, when bovine colostrum was administered immediately after purified IgG, the amount of swine IgG absorbed was 50–70% greater than in controls. Mature milk failed to have the same influence. Finally, in experiments in which the amount of purified swine IgG administered varied from 1.0 to 8.0 g, absorption was directly proportional to the amount administered. When these data were compared with data on naturally reared piglets, the same proportionality was seen and indicated a consistent 1:2.5 to 1:3 ratio of ingested IgG (g) to the maximal serum level of immunglobulin (mg/ml) resulting from absorption. IgA and IgM follow a similar pattern. The data are consistent with a regulated absorption mechanism, that appears to be lost very quickly after the initial ingestion of food. Heterologous protein and lactose alone can switch off this absorption mechanism, thus arguing against “gut closure” by a mechanism of receptor saturation by absorbed IgG. Bovine colostrum, when compared to mature milk, is able to augment the absorption of swine IgG by an unknown mechanism.

Antigen-Induced Changes in the Proportion of Antigen-Binding Cells Expressing IgM, IgG, and IgD Receptors

Abstract Changes in the isotype of the antigen receptor after immunization were assessed by using antigen-binding cells (ABC) from mouse spleen specific for sheep erythrocytes (SRC). Rabbit antisera specific for mouse heavy chains µ, γ, and δ, as well as polyspecific anti-Ig were used to inhibit SRC binding to the receptors of nonimmune ABC and immune ABC 5 days after immunization with SRC. Nonimmune ABC were more heterogeneous than immune ABC in their sensitivity to inhibition by polyspecific anti-Ig and anti-µ in that they included a greater proportion of cells inhibited by low concentrations of these antisera. The maximum percent of cells inhibitable by anti-µ (60 to 80%) did not change after immunization. Whereas IgG was not detectable on nonimmune ABC, after immunization 40 to 50% of the ABC expressed IgG. The proportion of ABC with IgD receptors fell from about 45% in nonimmune mice to around 25% in 5-day immune mice. From the inhibition produced by two or three antiheavy chain sera present individually or simultaneously, the proportion of cells bearing various combinations of surface Ig isotypes were estimated. Thus, nonimmune and immune ABC-bearing IgD also appeared to bear IgM although a few immune ABC expressed only IgM. In immune ABC, IgG-bearing ABC overlapped extensively with the IgM-bearing population but not with the IgD-bearing population. ABC bearing IgD alone were not detected, but immune animals probably contained µ+δ+γ+ ABC. These results suggest that antigen contact with specific ABC triggers changes of receptor isotypes during the expansion of the ABC population including a partial loss of IgD and the appearance of IgG.

Serum and colostrum immunoglobulin levels in the Northern Fur Seal Callorhinus ursinus

IgG, IgM, and IgA were measured in the serum and colostrum of adult and immature Northern Fur Seals (Callorhinus ursinus). Levels of these immunoglobulin classes in adults were comparable to those in terrestrial mammals. However, maternal transfer of immunoglobulin to neonatal pups either transplacentally or via the colostrum was low. The rate of appearance of IgG and IgA in the serum of pups from 3 days to 4 months was less than in most terrestrial mammals. IgM was present at 19% of the adult average in full term pups and rapidly rose to 70% of the adult value by 5 weeks of age. The significance of these results in regard to rookery mortality of fur seal pups is discussed.

Actively Induced Platelet-bound IgG Associated With Thrombocytopenia in the Marmoset

Interspecies platelet immunizations among marmosets lead to antibody formation to the donor platelets and a profound thrombocytopenia, which when associated with anemia may result in death of the animal. This actively induced immonologic thrombocytopenia closely resembles two clinical disease entities manifesting autoimmune thrombocytopenia, posttransfusion purpura and idiopathic thrombocytopenic purpura. Although antibody to donor-type platelets could be demonstrated readily, antihost activity was most often nondetectable or, when present, was in very low titer. A consistent finding was the appearance of IgG on the host's platelets shortly after immunization and concomitant with the appearance of antidonor platelet antibody. In 3 of 13 immunized animals thromoocytopenia did not occur even though antibody was formed and the host's platelets became IgG positive. In those animals that recovered from the induced thrombocytopenia IgG-positive platelets were found for periods ranging from 30 to greater than 100 days. Splenectomy before or after immunization did not alter the sequential development of antibody formation, appearance of IgG-positive platelets, and thrombocytopenia. Eluates prepared from IgG-positive platelets contained IgG and platelet antigens; the eluted IgG could attach nonspecifically to platelets of host or donor (immunizing) type, in contrast to the species specificity demonstrated for IgG eluted from platelets that had beenmore » reacted in vitro with specific antibody. Platelets in a few normal, nonimmunized marmosets were found to have signficant amounts of IgG on their surface, comparable to that observed in the immunized animal; interestingly, such IgG-positive platelets were found among imported but not laboratory-bred marmosets.« less

Comparability of delayed hypersensitivity in various rodents: I. Regulatory mechanism of delayed footpad reactions in the hamster

A relationship between delayed footpad reaction and antibody production was observed in hamsters immunized with erythrocytes of the mouse (MRC), sheep (SRC), or chicken (CRC). (i) In hamsters immunized with MRC in incomplete Freund's adjuvant (IFA), delayed reactions were positive in spite of high titers of IgM. Delayed reactions became negative with the appearance of IgG in hamsters pretreated with mouse spleen cells. (ii) In those immunized with SRC in IFA, positive delayed reactions were elicited only in the absence of IgG. Delayed reactions were converted from negative to positive by treatment with cyclophosphamide before elicitation in the presence of IgG. (iii) After immunization with SRC in complete Freund's adjuvant (CFA) or CRC in IFA or CFA, positive delayed reactions were elicited in the presence of IgG. There may exist an unstable form of delayed footpad reactions, which is regulated by antibody production, and a stable form, which is not regulated. Suppression in the former may be ascribed to some mechanism which is sensitive to cyclophosphamide and may be related to the production of IgG but not IgM.

Appearance of IgG (Fc) Receptor(s) on Cultured Human Fibroblasts Infected with Human Cytomegalovirus

Cultured human diploid fibroblasts (WI-38) after infection with human cytomegalovirus (CMV) but not when uninfected, could hemadsorb sheep red blood cells (SRBC) coated with rabbit anti-SRBC IgG. The adsorption of IgG-coated SRBC to virus-infected cells was completely abolished if the tests were carried out in the simultaneous presence of rabbit antiserum elicited against CMV. Normal sera of rabbit or human origin as well as purified human IgG but not Fab fragment of human IgG could also abolish the binding of sensitized SRBC to CMV-infected fibroblasts. Active metabolism on the part of CMV-infected fibroblasts proved to be an important requisite for demonstrating binding of sensitized SRBC to their surfaces. By using an indicator Staphylococcus aureus to which rabbit antiserum against normal human IgG, IgM, or IgA was bound via Fc fragments, evidence has been obtained which suggests the existence of receptor(s) on CMV-infected WI-38 cells that react specifically with Fc region of human IgG.

PHYLOGENETIC EMERGENCE OF IMMUNOGLOBULIN CLASSES DISTINCT FROM IgM

SUMMARYThe low molecular weight immunoglobulin from the marine toad (Bufo marinus) was found to differ markedly from classical mammalian IgG immunoglobulin. Higher intact molecular weight of 168,000 ± 4000 was the result of larger heavy chains (61,400 ± 2300) than mammalian γ chains (50,000 daltons). The light chains were of normal molecular weight (23,000).Polyacrylamide gel electrophoresis in SDS buffers was shown to be a simple and reliable way of determining the type of heavy chain present in immunoglobulins from different species, despite the fact that the mobility of the chains in this system does not accurately reflect their molecular weight. Using this technique it was shown that the heavy chain from the LMW Ig present in Xenopus laevis, an anuran amphibian, and the chicken, a representative of the birds, showed similar properties to the toad LMW Ig heavy chain. In addition, the LMW Ig heavy chain from the possum (Trichosurus vulpecula), a marsupial, showed properties which were characteristic of classical γ heavy chains.We conclude that the LMW Ig present in anuran amphibians does not belong to the IgG class as had been previously thought. This Ig class appears to have been retained in the reptiles and birds. The appearance of IgG appears to be a relatively recent event, recurring at a time after the divergence of the mammalian line from the stem reptiles.

The immune response to viruses in calves. I. Response to Murray Valley encephalitis virus.

SummaryFollowing inoculation of Murray Valley encephalitis virus into calves there was an early transient IgM response. The appearance of IgG was only slightly later than the first appearance of IgM in three calves, and in one calf IgG was detected before IgM. The secondary response was characterized by the more rapid appearance of IgG and the virtual absence of IgM. The IgG was of the electrophoretically fast type; there was an almost insignificant amount of antibody activity in electrophoretically slow fractions. IgM and slow IgG had no complement-fixing activity. IgM and IgG showed different cross-reactions to other group B arboviruses. The different cross-reactions, and the appearance of IgG before IgM in one animal suggests that the switch-over from IgM to IgG synthesis in the response is not the result of either a total or a random proportion of cells producing IgM, changing to IgG production. The fact that the IgG was almost exclusively of fast electrophoretic mobility suggested that the virus antigenic components were strongly basic, and as this is contrary to the chromatographic properties of arboviruses, it is suggested that the virus particles must be broken down before making contact with the factors determining the type of immunoglobulin formed.

The immune response to viruses in calves: II. The response in young calves

SUMMARYInjections of virus in calves up to about 5 weeks of age caused either the production of both IgM and IgG, or the production of only IgG, or no detectable antibody. In all but one case priming for a secondary response occurred even in the absence of a detectable primary response. These results suggest that in the young calf immunological memory is more readily induced than IgG synthesis. IgM appeared by the 7th or 10th day, which was similar to the response in older calves. IgG was more variable in its appearances but was usually considerably delayed relative to the response in older calves. In general only low levels of IgM were formed in the primary response and it was virtually absent from the secondary responses. Higher levels of IgM were formed after reovirus inoculation than after Murray Valley encephalitis virus or Getah viruses. The delay in appearance of IgG was more pronounced in response to Getah than to reovirus or Murray Valley encephalitis virus. High levels of maternally derived passive antibody inhibited the development of an active response, although in one animal a response occurred in the presence of low levels of passive antibody.

Congenital rubella syndrome with immunoglobulin disorder

A child with the congenital rubella syndrome and immunoglobulin abnormalitiescharacterized by a tremendous increase in IgM, delayed appearance of IgG, and absence of IgA, is described. “Rheumatoid factor” and cold agglutinins were present. Treatment with an antiviral agent, l-adamantanamine, was thought to result in clinical improvement. An unusual feature of the case was the late development of retinitis and cataracts. A child with the congenital rubella syndrome and immunoglobulin abnormalitiescharacterized by a tremendous increase in IgM, delayed appearance of IgG, and absence of IgA, is described. “Rheumatoid factor” and cold agglutinins were present. Treatment with an antiviral agent, l-adamantanamine, was thought to result in clinical improvement. An unusual feature of the case was the late development of retinitis and cataracts.