Appearance Of IgG Antibodies Research Articles

Incidence and progression of Parvovirus B19 infection and molecular changes in circulating B19V strains in children with haematological malignancy: A follow up study

The present study was planned to estimate the incidence of human Parvovirus B19 infection and understand its progression in children suffering with hematological malignancy. The circulating B19V genotypes and viral mutations occurring in strains of B19V over one-year period were also studied. Children with malignancies were enrolled consecutively and were followed up for one-year period. Serum sample was collected at the time of enrolment and each follow up visit and was tested for anti B19V IgG and IgM as well as for B19V DNA. At least one B19V DNA positive sample from each patient was processed for sequencing. For patients positive for B19V DNA >1 time and at least 6 months apart, last positive sample from the same patient was also sequenced to study the nucleotide change over time. We have found very high incidence of B19V infection (100%) in the study population. All the patients tested positive for at least one B19V infection parameter (either antibodies or DNA) at least once, over one year of follow up. Cumulative percent positivity of anti B19V IgG, anti B19V IgM and B19V DNA was 85.3%, 45.2% and 72.1% respectively. Genotype 3b was reported, with occasional nucleotide change over one year period. DNA clearance was delayed in spite of appearance of IgG antibodies. Appearance of IgM class of antibodies was either delayed or absent. To conclude, children with haematological malignancies have high incidence of B19V infection with late and short lived serological response and persistence of DNA for long duration.

Early cytokine and antibody responses against Coxiella burnetii in aerosol infection of BALB/c mice

Coxiella burnetii, a Gram-negative intracellular bacterium, can give rise to Q fever in humans and is transmitted mainly by inhalation of infected aerosols from animal reservoirs. Serology is commonly used to diagnose Q fever, but the early cellular immune response—i.e., C. burnetii–specific interferon γ (IFN-γ) production in response to antigen challenge—might be an additional diagnostic. Detection of IFN-γ responses has been used to identify past and chronic Q fever infections, but the IFN-γ response in acute Q fever has not been described. By challenging immunocompetent BALB/c mice with aerosols containing phase I C. burnetii, the timing and extent of IFN-γ recall responses were evaluated in an acute C. burnetii infection. Other cytokines were also measured in an effort to identify other potential diagnostic markers. The data show that after initial expansion of bacteria first in lungs and then in other tissues, the infection was cleared from day 10 onwards as reflected by the decreasing number of bacteria. The antigen-induced IFN-γ production by splenocytes coincided with emergence of IgM phase II antibodies at day 10 postinfection and preceded appearance of IgG antibodies. This was accompanied by the production of proinflammatory cytokines including interleukin (IL) 6, keratinocyte-derived cytokine, and IFN-γ–induced protein 10, followed by monocyte chemotactic protein 1, but not by IL-1β and tumor necrosis factor α, and only very low production of the anti-inflammatory cytokine IL-10. These data suggest that analysis of antigen-specific IFN-γ responses could be a useful tool for diagnosis of acute Q fever. Moreover, the current model of C. burnetii infection could be used to give new insights into immunological factors that predispose to development of persistent infection.

Prolonged anemia by superinfection of parvovirus B19 in a boy with enterohemorrhagic Escherichia coli O157-associated hemolytic uremic syndrome

We report a 3-year-old boy with enterohemorrhagic Escherichia coli (EHEC) O157-associated hemolytic uremic syndrome (HUS). His anemia was associated with decreased reticulocyte count and persisted after the recovery from HUS. Superinfection of parvovirus B19 (PVB19) was proven by a transient febrile episode associated with IgM antibodies to the virus and the delayed appearance of IgG antibodies and typical rashes. We conclude that PVB19 infection could induce severe persistent anemia in EHEC-associated HUS. Reticulocytopenia is a clue to the diagnosis in such cases.

Effect of maternal diet during lactation on development of bovine insulin–binding antibodies in children at risk for allergy

Background: The role of exposure to dietary antigens through maternal milk is intriguing, because it may result either in immunization or in tolerance. Exposure to cow's milk proteins results in antibody formation against bovine insulin in infants at risk for type 1 diabetes. Objective: To study the appearance of IgG antibodies to bovine and human insulin in infants with an atopic family history whose mothers followed a cow's milk–free diet during the first 3 months of lactation. Methods: In a prospective cohort study on prevention of food allergies, 123 infants were exclusively breast-fed or received supplementation with a hydrolyzed casein-based formula (Nutramigen) until the age of 6 months. The mothers either avoided cow's milk during the first 3 months of lactation (diet group) or had an unrestricted diet (nondiet group). The levels of IgG antibodies to bovine and human insulin were determined by enzyme immunoassay at 3, 6, 12, and 18 months and at 4 years. In addition, cord blood was obtained at birth and a maternal sample at delivery. Results: At 3 months, IgG antibodies to bovine insulin were low in both dietary groups (median levels 0.150 and 0.114 optical density units in the diet and nondiet groups). After exposure to dietary insulin, IgG antibodies to bovine insulin increased in both groups, reaching a peak at 12 months in the nondiet group and at 18 months in the diet group. At 18 months, IgG antibodies to bovine insulin were lower in infants in the nondiet group than in infants in the diet group (0.287 vs 0.500, P < .0001). At 4 years, the antibodies no longer differed between the groups. Conclusion: The exposure to cow's milk proteins through breast milk during the first 3 months of life resulted in decreased levels of antibodies to dietary bovine insulin at 18 months of age, suggesting a role for breast milk antigens in early tolerance induction. (J Allergy Clin Immunol 2000;106:302-6.)

Different H-2 subregions influence immunization against retrovirus and immunosuppression.

Friend murine leukaemia virus complex (FV) causes an immunosuppressive retrovirus-induced disease. In certain mouse strains, FV shows striking similarities to human immunodeficiency virus (HIV) infection in man in that infected mice have severe T-cell immunosuppression but also develop virus-neutralizing antibodies incapable of eliminating infected cells. Previously we noted the influence of mouse major histocompatibility complex (H-2) genes on both FV-induced immunosuppression and on ability to protect mice against FV by immunizing with a vaccinia-Friend murine leukaemia helper virus (F-MuLV) envelope (env) recombinant virus. Here we show that different subregions of H-2 are involved in susceptibility to virus-induced immunosuppression (H-2D subregion) and protective immunization with a recombinant vaccinia virus (H-2K or I-A subregions). Thus, susceptibility to virus-induced immunosuppression does not preclude protection by vaccinia-Friend immunization. The mechanism of protection seems to involve priming of immune T cells, and not initial induction of neutralizing antibodies or cytotoxic T lymphocytes (CTL) (ref.2). Subsequent virus challenge generates a secondary response, resulting in appearance of IgG antibodies and CTL. In human HIV infection there could also be host genetic influences on elements of disease pathogenesis, such as immunosuppression, and on the success of T-cell priming by potential protective vaccines.

Sex steroids and the immune system—I. Sex difference in autoimmune disease in NZB/NZW hybrid mice

Hybrid NZB/NZW (B/W) mice develop an autoimmune disease that has many of the characteristics of human systemic lupus erythematosis including marked sex differences. Studies were done to investigate the role of gonadal steroids in modulating expression of disease. Estrogens accelerate and androgens slow the time course of appearance of antibodies to nucleic acids and death when administered by implants. Castration of females does not influence survival whereas castrated males have earlier development of antibodies and accelerated mortality similar to intact females. In general, administration of estradiol or progesterone accelerates the appearance of IgG antibodies to both DNA and Poly A whereas dihydrotestosterone or testosterone retarded antibody formation. Surprisingly, coadministration of estradiol and dihydrotestosterone increased the mortality rate in both sexes. Studies with estradiol demonstrated receptor-like binding in cytosol and nuclear extracts prepared from the thymus of several strains of mice whereas DHT binding could not be found. Administration of estradiol elevated total receptor binding in the thymus of male B/W mice. While complex mechanisms with other systems are involved, it appears that the sex steroids can influence antibody formation by interaction with the thymus gland.

Effect of castration and sex hormone treatment on survival, anti-nucleic acid antibodies, and glomerulonephritis in NZB/NZW F1 mice.

NZB/NZW F1 mice of both sexes were castrated at 2 wk of age and implanted subcutaneously with silastic tubes containing either 5-alpha-dihydrotestosterone or estradiol-17-beta. Mice receiving androgen showed improved survival, reduced anti-nucleic acid antibodies, or less evidence of glomerulonephritis as determined by light, immunofluorescent, and electron microscopy. By contrast, opposite effects were observed in castrated mice receiving estrogen. Intact male NZB/NZW F1 mice received androgen implants at 8 mo, an age when they develop an accelerated autoimmune disease associated with a decline in serum testosterone concentration. Such treated mice had improved survival and reduced concentrations of antibodies to DNA and to polyadenylic acid (Poly A). Prepubertal castration of male NZB/NZW F1 mice results in an earlier appearance of IgG antibodies to Poly A. This effect of castration was prevented if neonatal thymectomy was also performed.

Studies in infantile marasmus. IV. Impairment of immunologic responses in the marasmic pig.

Extract: We investigated the immunologic responses in an experimental model, the marasmic piglet. Two litters of miniature piglets of the Pitman Moore strain [46] were divided into two groups with five of the animals given normal diet and eight subjected to dietary restriction. The dietary intake of the experimental piglets was restricted to prevent further significant weight gain after the age of 35 days. The experimental animals displayed a well developed characteristic picture of severe undernutrition after 3 months of dietary restriction. Concentrations of immunoglobulins G and M (IgG and IgM) in both experimental and control pigs were similar. Antibody titers against erythrocyte A-antigen of experimental pigs were consistently lower (Table IV). Antibody responses after immunization to tetanus toxoid, sheep erythrocytes, and bacterio-phage πX 174 were remarkably similar in both groups (Tables V and VI). The experimental animals had a delay in appearance of IgG antibody after primary immunization with bacteriophage πX 174. The physiologic lymphecytosis found in the control animals was absent in the experimental group. All lymphoid organs examined in the marasmic pigs displayed marked atrophy as compared to the control animals. No tissues were identified grossly as thymus in the neck or anterior mediastinum of the experimental animals. The germinal centers of the spleen and lymph nodes were poorly formed in the experimental animals. Delayed hypersensitivity to 2,4-dinitro-fluorobenzene was demonstrated in only one of the five experimental animals while all four control animals demonstrated delayed hypersensitivity when tested at the same age. Four experimental pigs and three control pigs were immunized with BCG vaccine at 10 months of age. The mean diameter of tuberculin reaction of the experimental group was 6.5 mm; that of the controls was 27 mm when tested 4 weeks later. Both full thickness skin grafts and split thickness grafts underwent a delayed rejection in the experimental group. Lymphocyte transformation with phytohemagglutinin was studied at 6, 9, and 14 months of age in both control and experimental animals with similar results in both groups (Table VIII). Leukocytes from three experimental pigs had no increase in uptake of thymidine when tested in mixed leukocyte culture. Leukocytes from five experimental animals and three control pigs had normal leukocyte bactericidal activity against Staphylococcus aureus and Serratia marcescens. These studies provide presumptive evidence that marasmic pigs have defects in both humoral and cellular immunity. The deficiency in cellular immunity seemed greater and was manifest by thymic involution, lymphopenia, a decreased capacity to express delayed hypersensitivity, delayed homograft rejection, and absence of reactivity in the mixed leukocyte culture. Speculation: Clinical experience and recent experimental studies indicate that malnutrition decreases resistance to infection. The results presented show that cell-mediated immunity is impaired in malnutrition. Much of the immunodeficiency in malnutrition may be mediated by hyperadrenocorticism.

Immune Response of Pigs to Inactivated Foot-and-Mouth Disease Vaccines: Response to DEAE-Dcxtran and Saponin Adjuvanted Vaccines

SUMMARY The immune response of pigs to inactivated DEAE-dextran and saponin adjuvanted foot-and-mouth disease (FMD) vaccines differed front their response to emulsion vaccines. A single dose of a DEAE-dextran vaccine stimulated reasonable serum neutralizing antibody concentrations which reached their peak at 14 days after vaccination and then decreased. Duration of immunity was short and lasted from 1 to 3 months. A single dose stimulated the appearance of IgG antibodies. A good anamnestic response resulting in a much longer duration oj immunity followed secondary vaccination at between 1 and 3 months after primary vaccination. A single dose of a saponin vaccine gave a true IgM primary response with peak antibody concentrations at 7 days after vaccination. By 21 days no detectable serum antibodies were present, but the animals werecapable of giving a moderate anamnestic response to a second inoculation at this time which resulted in the appearance of IgG antibodies. It is suggested that the pig requires repeated stimulation with inactivated FMD antigen for an adequate level of immunity to be maintained. This occurs following vaccination with emulsion vaccines but docs not occur in convalescent pigs or following inoculation with DEAE-dextran or saponin vaccines.

Fluoroimmunoelectrophoresis

An agarose immunoelectrophoresis technique is described which uses fluorescein isothiocyanate labeled antigen and antibodies. The technique can be used for the detection and identification of the main antibody classes, for revealing non-precipitating reactions as well as for localizing the combining sites on different antibody fragments (Fab fragments and H chains). The early appearance of IgG antibodies was also evidenced by means of this technique.