Increase In IgA Levels Research Articles

TLR9 mediates IgA production in the porcine small intestine during PEDV infection

IgA plays a vital role in defending against the infectious pathogens. However, the specific regulatory pathways involved in IgA secretion in the context of PEDV infection have remained elusive. Therefore, in this study, we explore the molecular mechanisms underlying IgA secretion in response to infection, with a particular focus on PEDV, a devastating enteric virus affecting global swine production. Our investigation begins by examining changes in IgA concentrations in both serum and small intestinal contents following PEDV infection in 2- and 4-week-old pigs. Remarkably, a significant increase in IgA levels in these older pigs post-infection were observed. To delve deeper into the regulatory mechanisms governing IgA secretion in response to PEDV infection, isolated porcine intestinal B cells were co-cultured with monocytes derived DCs (Mo-DCs) in vitro. In the intestinal DC-B cell co-cultures, IgA secretion was found to increase significantly after PEDV infection, as well as upregulating the expression of AID, GLTα and PSTα reflecting isotype switching to IgA. In addition, the expression of TLR9 was upregulated in these cultures, as determined by RT-qPCR and western blotting. Moreover, our findings extend to in vivo observations, where we detected higher levels of TLR9 expression in the ileum of pig post PEDV infection. Collectively, our results highlight the ability of PEDV to stimulate the generation of IgA, particularly in elder pigs, and identify TLR9 as a critical mediator of IgA production within the porcine intestinal microenvironment during PEDV infection.

Protective Role of Limosilactobacillus fermentum Lf2 and Its Exopolysaccharides (EPS) in a TNBS-Induced Chronic Colitis Mouse Model

Limosilactobacillus fermentum Lf2 (Lf2) is an autochthonous strain that produces high levels of exopolysaccharides (EPS). The objective of this work was to evaluate the probiotic potential of Lf2 and its relationship with these metabolites in a mouse model of TNBS (trinitrobenzene sulfonic acid)-induced chronic colitis. Mice were treated intrarectally with increasing doses of TNBS resuspended in 50% ethanol for 14 days. In parallel, they received different treatments by gavage (lactose 10% as the matrix): freeze-dried Lf2 (L); purified EPS (E); and lactose 10% (T). A healthy control group (H) was treated with 50% alcohol without TNBS (intrarectally) and 10% lactose (by gavage). In the small intestine, there was a significant increase in IgA levels for the group that received EPS and a decrease in IFN-γ for mice treated with the strain compared to the other groups. In the large intestine, IL-2 and IFN-γ presented the lowest levels in the groups treated with EPS and the strain. The concentrations of acetic and propionic acids in mice that received Lf2 were the highest, while the levels of butyric acid were comparable to the healthy control group. An increase in the abundance of SCFA-producing bacteria was observed for mice treated with EPS and the strain in comparison with the colitis control group. The enzyme activity of catalase was higher in all the treatments compared to the TNBS-induced colitis control mice. To summarize the results obtained, a principal component analysis (PCA) was performed, clearly grouping the treatments in different clusters according to the variables studied. This is one of the first studies to address the role of a potential probiotic strain in a chronic colitis mouse model, trying to elucidate the relationship between its properties and the EPS synthesized.

Solitary extramedullary plasmacytoma of the gingiva—A case report with literature review

Abstract Extramedullary solitary plasmacytoma (EMP) is a plasma cell neoplasm involving the soft tissues without the involvement of the bone marrow. In this case report, we present an isolated soft tissue growth on the lingual gingiva of the left mandibular canine-premolar region diagnosed as EMP based on clinical, histological, and laboratory results. Orthopantomogram and occlusal radiographs showed no osteolytic lesions. Hematoxylin and Eosin staining showed sheets of inflammatory cells, predominantly atypical plasma cells with varying degrees of differentiation showing features of pleomorphism, and multinucleated giant cells with intervening collagen fibers. Positive immunoreactivity for CD56, CD138, and kappa light chain restriction were observed. Serum protein electrophoresis demonstrated an increase in IgA levels and immunofixation electrophoresis confirmed the presence of the M band in the IgG and kappa lanes, indicating monoclonal gammopathies. Based on the above findings, the case was diagnosed as EMP; the consultant pathologist, however, recommended excluding multiple myeloma.

Acute and chronic effects of physical exercise on IgA and IgG levels and susceptibility to upper respiratory tract infections: a systematic review and meta-analysis.

This systematic review and meta-analysis aimed at evaluating acute and chronic effects of physical exercise on IgA and IgG levels, as well as its relationship with the susceptibility to develop upper respiratory tract infections (URTI). This systematic review and meta-analysis was conducted and reported in accordance with PRISMA statement. A systematic search of PubMed, Web of Science, and EMBASE was performed in July 2020. This systematic review and meta-analysis included studies in which participants performed acute exercise or chronic physical training and were subjected to analyses of URTI incidence and concentrations of IgA and IgG. The selected studies for systematic review were divided into the following three groups: (I) trials that evaluated the effects of acute exercise in sedentary subjects, (II) trials that evaluated the effects of acute exercise in athletes/trained individuals, and (III) trials that evaluated the effects of chronic physical training on the incidence of URTI, as well as on the levels of IgA and IgG. Acute exercise increases the IgA levels in trained subjects but does not affect its levels in untrained subjects. Such increase in IgA levels induced by acute exercise is greater in trained individual that performed ultramarathon. On the other hand, chronic physical training reduces IgA levels in both trained and untrained subjects, does not change IgA levels in non-military subjects, besides from not affecting IgG levels. The present systematic review and meta-analysis indicates that acute exercise positively influences IgA levels in trained individuals, being this effect pronounced when a strenuous exercise such as ultramarathon is executed. Chronic physical training, in turn, does not affect IgG levels.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00424-022-02760-1.

Antiviral activity of a novel mixture of natural antimicrobials, in vitro, and in a chicken infection model in vivo

The aim of this study was to test in vitro the ability of a mixture of citrus extract, maltodextrin, sodium chloride, lactic acid and citric acid (AuraShield L) to inhibit the virulence of infectious bronchitis, Newcastle disease, avian influenza, porcine reproductive and respiratory syndrome (PRRS) and bovine coronavirus viruses. Secondly, in vivo, we have investigated its efficacy against infectious bronchitis using a broiler infection model. In vitro, these antimicrobials had expressed antiviral activity against all five viruses through all phases of the infection process of the host cells. In vivo, the antimicrobial mixture reduced the virus load in the tracheal and lung tissue and significantly reduced the clinical signs of infection and the mortality rate in the experimental group E2 receiving AuraShield L. All these effects were accompanied by a significant reduction in the levels of pro-inflammatory cytokines and an increase in IgA levels and short chain fatty acids (SCFAs) in both trachea and lungs. Our study demonstrated that mixtures of natural antimicrobials, such AuraShield L, can prevent in vitro viral infection of cell cultures. Secondly, in vivo, the efficiency of vaccination was improved by preventing secondary viral infections through a mechanism involving significant increases in SCFA production and increased IgA levels. As a consequence the clinical signs of secondary infections were significantly reduced resulting in recovered production performance and lower mortality rates in the experimental group E2.

Effect of whey-pearl millet-barley based probiotic beverage on Shigella-induced pathogenicity in murine model

Abstract The aim of the current study is to investigate the efficacy of a probiotic beverage prepared from underutilized resources in preventing Shigella-induced pathogenicity in mice model. Probiotic beverage having high counts (1011–1012, cfu/ml) was prepared from whey-skim milk (60:40, v/v), germinated pearl millet flour (4.73%, w/v) and liquid barley malt extract (3.27%, w/v) with Lactobacillus acidophilus NCDC 13. Albino mice were challenged using pathogenic Shigella dysenteriae orally. Mice were sacrificed on the 2nd, 5th and 8th days post-challenge and colonization of pathogen and IgA concentration in intestine fluids was estimated. Long term (7 days) feeding of probiotic beverage stimulated immune system by enhanced secretion of IgA. Further inhibition of pathogen was clearly observed in all organs and feaces. However, short term (2 days) feeding was not much effective as there was non-significant increase in IgA level in intestine fluids, whereas control sample was unable to inhibit the infection.

Identification of the Immunological Profile in Some Egyptian Children with β- Thalassaemia Major Under Different Treatment Modalities in El Minia Region

Abstract Background: β-thalassaemia major is one of the chronic hemolytic anemias resulting from defect in β-globin chain. It requires frequent blood transfusion plus other treatment modalities. These treatment modalities may be associated with certain immunologic modulations. Objective: To assess the immunity status in children with β-thalassaemia major under different treatment regimens within El Minia, Egypt. Subjects and Methods: One hundred forty-four children were enrolled and classified into four groups. Thirty-six β-thalassaemia patients treated only with blood transfusion (group I). Thirty-six patients treated with transfusion and iron chelation (group II). Thirty-six patients treated with transfusion, iron chelation and subjected to splenectomy (group III). Group IV involved thirty-six apparently healthy age and sex matched children. CBC plus serum levels of ferritin, IgA, complement C3 and C4 were measured along with detection of CD3+, CD4+, CD8+, CD19+ and CD56+ lymphocyte percentages and absolute counts. Results: IgA levels were significantly higher in thalassaemia patients compared to controls (p<0.001) plus highly significant increase in IgA levels in splenectomized patients than non-splenectomized (p<0.001). Levels of C3 were significantly decreased in all patients compared with controls (p=0.001) with a highly significant decrease in C3 levels in splenectomized patients than non splenectomized ones (p<0.001) but no statistical difference between their C4 levels. Significant statistical differences were revealed regarding CD3+, CD4+ and CD8+ T lymphocyte percentages within thalassaemia groups when compared to each other’s and to controls. Splenectomized patients had higher significant levels regarding serum ferritin (p=0.02) along with CD3+ (p=0.05), CD4+ (p=0.05) and CD8+ (p=0.037) lymphocyte percentages compared to non-splenectomized. CD19+ lymphocyte percentages were significantly higher while CD56+ lymphocyte percentages were significantly lower in all patients compared with controls (p=0.02 and 0.05). Conclusion: Immune modulation occurs in thalassaemia patients with regional specific variations and is related to variations in treatment modalities.

Temporary Immunity of Blackbelly Lambs Reinfected with Trichostrongylus colubriformis

Background: Trichostrongylus colubriformis is one of the most prevalent gastrointestinal nematodes of sheep in warm climates. In this nematode species, anthelmintic resistance (AR) has been reported, which has motivated the search for alternative methods to control it. One practice is to increase the immune response level through the selection of animals with natural resistance, such as Blackbelly sheep. The aim of this study was to investigate the response of IgA and IgG in serum and saliva and the level of cells involved in the acquired resistance in Blackbelly lambs after single artificial reinfection with a resistant strain of Trichostrongylus colubriformis.Materials, Methods &amp; Results: Sixteen weaned lambs grazed for one month in nematode-contaminated grasslands. All the lambs were treated with Albendazole and Levamisole; later, they were stabled for two months. After that, eight lambs were re-infected with 6000 larvae of T. colubriformis and other eight lambs remained naturally infected. In addition, eight nematode-free lambs raised in cages, served as negative control. Blood samples were taken fortnightly to determine packed cell volume (PCV, %), plasmatic protein (g dL-1), as well as absolute and differential leukocytes. The eggs per gram of feces (EPG) were recorded. An indirect ELISA against T. colubriformis Ag was performed to determine the IgG and IgA levels. All data were analyzed by repeated measures. The EPG in the re-infected group increased after 34 days (625 ± 287), while in the naturally infected group it remained close to 200 ± 158 throughout the study. The control lambs did not show any infection. The PCV (29.4 ± 3.4 %), basophils (44 ± 74), lymphocytes (8443 ± 2845) and monocytes (77 ± 91) counts were not affected by infection. The IgA OD against T. colubriformis increased significantly after 15 days post-infection (dpi) in the re-infected lambs (1.69 ± 0.5, 80% with regards to standard). With IgG was not possible to distinguish the effect of infection.Discussion: Highly persistent infection of T. colubriformis was observed for at least four months in the naturally infected group despite having been treated with anthelmintics. It is a significant problem because this species has a high prevalence in the region of study and shows anthelmintic resistance. For such reason, is important to evaluate the ability of the animal to develop an immune response. In other study, a natural reduction in the fecal egg count (FEC) was indicated at 100 dpi in the same species, but in the present work, the FEC could not be reduced until around 120 days when the naturally infected lambs were evaluated. The larger number of neutrophils and leukocytes in both the naturally infected and re-infected groups implies a sustained response for a long time. While the higher counts of eosinophils only in the re-infected group were produced as an immediate response to infection with T. colubriformis. Similarly, with a single infection of T. colubriformis, in Santa Ines sheep the infected lambs showed significantly higher levels of serum IgA than the control group. In this case, differences in IgA activity were observed between the re-infected lambs and the other groups at fifteen dpi, but the basal levels of IgA in the naturally pre-infected lambs were maintained at least five weeks after infection. In conclusion, an increase in the peripheral immune response in lambs re-infected with T. colubriformis resulted from the increase in IgA levels in serum and saliva, and increase in the number of peripheral eosinophils, total leukocytes and neutrophils. Re-infected lambs had a higher level of IgA than naturally infected lambs and control lambs, making possible to promote the immune response with a single re-infection with Trichostrongylus colubriformis.

PP076-SUN NUTRITIONAL STATUS AND BODY COMPOSITION OF PATIENTS WITH TYPICAL GERIATRIC BONE FRACTURES

to assess nutritional and immunological biomarkers. Fecal samples were collected before and after the intervention. Results: Increases in IgA levels tended to be higher in the BB536 group than in the placebo group. The percentage of subjects with a positive antibody titer toward A/H1N1 was significantly higher at week 6 in the BB536 group than in the placebo group. NK cell activity decreased significantly only in the placebo group during the intervention period. Changes in NK cell activity tended to be higher in the BB536 group compared to the placebo group. Significantly higher numbers of bifidobacteria and B. longum subsp were observed in the BB536 group after the intervention. Conclusion: Long-term ingestion of the probiotic BB536 modulated innate and adaptive immune function. There were no adverse effects from the ingestion of BB536. These results suggest that BB536 ingestion could help improve the health status of the elderly.

Biological Effect of Leaf Aqueous Extract ofCaesalpinia pyramidalisin Goats Naturally Infected with Gastrointestinal Nematodes

Forty-eight goats naturally infected with gastrointestinal nematodes were randomly divided into four groups (n = 12): negative control (G1) (untreated), positive control (G2) (treated with doramectin, 1 mL/50 Kg b.w.), and G3 and G4 treated with 2.5 and 5 mg/Kg b.w. of a leaf aqueous extract of Caesalpinia pyramidalis (CP). Fecal and blood samples were regularly collected for the evaluation of fecal egg count (FEC), hematological and immunological parameters to assess the anthelmintic activity. In treated animals with CP, there was noted a significant reduction of 54.6 and 71.2% in the mean FEC (P < 0.05). An increase in IgA levels was observed in G3 and G4 (P < 0.05), during the experimental period, suggesting that it was stimulated by the extract administration. In conclusion, the results showed that CP provoked a protective response in infected animals treated with them. This response could be partly explained by the CP chemical composition.

Association of anti-IgA antibodies with adverse reactions to γ-globulin infusion

Association of anti-IgA antibodies with adverse reactions to γ-globulin infusion

Minimal Effects on Immune Parameters Following Chronic Anti-TGF-β Monoclonal Antibody Administration to Normal Mice

Mice genetically deficient in TGF-β1 or TGF-β signaling capacity in T or B cells demonstrate profound immune dysregulation, as evidenced by increased lymph node size, expression of markers of memory/activation on T cells, inflammation in a variety of tissues and development of autoantibodies. However, this constant and complete lack of TGF-β1 or TGF-βR signaling may not reflect effects of TGF-β neutralization using antibodies in mature animals. Thus, the present studies were designed to determine if administration of an anti-TGF-β monoclonal antibody (neutralizes TGF-β1, 2 and 3) to mature, normal mice results in evidence of immune dysregulation or immune-mediated pathology. An initial study examined daily administration of 0.25, 0.75 and 2.5 mg/kg of anti-TGF-β to mice for three weeks, achieving blood levels of as high as 9 mg/ml. Comprehensive hematological and histopathological evaluation showed no evidence of pathology. A second study was designed to extend the antibody treatment period and further examine the functional status of the immune system. Mice were injected with 1 mg/mouse (approximately 50 mg/kg) of anti-TGF-β (1D11) three times per week achieving circulating blood levels of 1–2 mg/ml. Many parameters of immune status were assessed, including natural killer (NK) cell activity, lymphocyte proliferative responses, phagocytic activity, phenotypic assessment of leukocyte subsets, and serum measurements of proinflammatory cytokines, autoantibodies and immunoglobulin isotypes. In addition, histopathological assessment of heart, lungs, liver, kidney, salivary glands, skin, spleen and lymph nodes was also performed. Very few of the multiple immune parameters examined showed detectable changes in anti-TGF-β-treated mice. Changes that were observed were primarily restricted to the spleen and included increased spleen cell recoveries, increased percentages of macrophages, decreased percentages of NK cells, decreased phagocytic activity, decreased proliferative responses to mitogens and slight increases in T and B cells displaying an activated phenotype. Many of these same parameters examined in the lymph nodes were not altered by the anti-TGF-β treatment. The thymus was decreased in size, but altered only slightly in one population of developing T cells. Most of the changes observed were modest and returned to control levels after discontinuation of treatments. The only serological finding was an increase in IgA levels in anti-TGF-β-treated mice, but not in any other isotype. Finally, there was no evidence of increased inflammation in any of the peripheral tissues examined in the anti-TGF-β-treated mice. In conclusion, although there were changes in some of the immunological parameters examined in these studies, they were few and typically reversed following discontinuation of treatment. The modest nature of the changes observed in these studies is particularly evident when compared to published data of those same parameters examined in mice genetically deficient in TGF-β1 or mice having TGF-β unresponsive T or B cells. Thus, there does not appear to be any significant immune dysregulation detectable after long-term antibody-mediated neutralization of TGF-β in normal mice.

Salivary albumin, total protein, IgA, IgG and IgM concentrations and occurrence of some periodontopathogens in HIV-infected patients: a 2-year follow-up study.

HIV infection reduces oral defensive mechanisms and may affect mucosal integrity. Differences in salivary protein concentrations and periodontopathogenic bacteria were studied in 56 HIV-infected patients with respect to their disease phase. Thirty-three patients were followed up for 2 years. Fifty-three healthy subjects of corresponding age and sex were studied as controls. At baseline, salivary albumin, total protein, IgA, and IgM levels were significantly higher (P<0.05-0.0001) in all phases of HIV infection, except the asymptomatic (ASX) phase, when compared with the control group. IgG levels were significantly increased in all phases except the ASX phase (P<0.05). After 2 years, salivary total protein, IgG, and IgM levels were still higher (P<0.05-0.005) in all HIV phases when compared with the control group (P<0.05-0.005). The albumin level was significantly higher in the ASX phase (P<0.005) and in the AIDS-related complex phase (ARC) (P<0.05), while the increase in IgA level was significant only in the ARC phase (P<0.005). Periodontopathogenic bacteria analyzed by PCR were detected both in the patients and the non-infected, but a statistically significant difference in the carriage percentage between the follow-up lymphadenopathy syndrome phase (LAS) and the control group was found only in Porphyromonas gingivalis (P<0.05) and Bacteroides forsythus (P< 0.0001). Thus, HIV infection appeared to cause a significant increase in the studied salivary proteins, suggesting leakage of serum components into the mouth.

Serum Responses to the Combination of Epstein-Barr Virus Antigens in Patients With Nasopharyngeal Carcinoma in a Follow-up Study

Background. Elevated serum IgA to Epstein-Barr virus (EBV) antigens was frequently found in patients with nasopharyngeal carcinoma (NPC). Recent evidence indicated that EBV in NPC patients could be a mixture of latent and active infections. Methods. In this longitudinal study, we therefore used six EBV antigens from both latent and acute phases of infection to evaluate NPC patients. Immunosensitivity was determined using enzyme-linked immunosorbent assay, and immunospecificity was assessed using immunoblot. Results. Levels of serum IgA to EBV in NPC patients were significantly higher than the levels in the healthy control subjects. Persistent high IgA titer or the aberrant increase of IgA level indicated a high risk of disease recurrence and early distant metastasis. Conclusions. Disease progression of NPC was proceeded by the increase of IgA titer to EBV antigens. Measurement of serum IgA to a panel of EBV antigens from both latent and acute viral . infections could, therefore, provide a predictive index for NPC response.

Upper respiratory infections in children: response to endonasal administration of IGA

Children, 36, predisposed to frequent upper respiratory infections were treated with endonasal administration of an IgA enriched preparation or placebo in a randomized double blind trial. We found a reduction in the number of infectious episodes and in the number of enlarged regional lymph nodes. Also, an increase of IgA levels in saliva in the treated group was observed, probably not only due to the effect of IgA supplementation, but also to an immunoregulatory effect on the mucosa caused by the preparation administered. We found this therapy very useful in the prophylaxis of upper respiratory infections, being the nasal administration very convenient to be used in children.

Enhancement of the humoral immune response and resistance to bacterial infection in mice by the oral administration of a bacterial immunomodulator (OM-89).

We investigated the effects of an Escherichia coli-derived product (OM-89) in mice. The oral administration of OM-89 led to a significant (p less than 0.05, Student's t test) increase in the levels of IgA in intestinal secretions, which was at maximum 25 days after the end of the treatment, when a two-fold increase in IgA levels was observed. The i.p. inoculation of OM-89 induced the stimulation of anti-SRBC plaque-forming cells (PFC) in the spleen. The effect of OM-89 was dose-dependent and produced up to a 9-fold increase in PFC in the treated mice when compared to untreated controls. The oral administration of OM-89 proved to be effective in the enhancement of resistance to challenge i.p. inoculation with E. coli. 32% of OM-89-treated mice showed resistance to this experimental infection at minimal LD100. The combined effects of low environmental temperature and cyclophosphamide (CY) immunosuppression enabled us to enhance differences in survival rates in experiments on the modulation of resistance towards Pseudomonas aeruginosa infection. The oral treatment with the immunomodulator induced a significant (p less than 0.05, Student's t test) level of protection in CY-immunosuppressed mice to the intranasal infection with P. aeruginosa, when mice were kept at low environmental temperature right after the bacterial challenge. The protective effect of OM-89 treatment was dependent on both the environmental temperature and the timing of the experiment.

Serum IgA in nasopharyngeal carcinoma

After the demonstration of tumour specific antigens by Foley (1953) and Prehn and Maine (1957) a great deal of experimental and clinical data have established the role of humoral immunity in various aspects of malignancy. Serum IgA have been studied in 15 cases of carcinoma nasopharynx and a significant increase in IgA levels observed have been correlated with the exposure of the mucosa of oral cavity to environment and its stimulation leading to increased synthesis of the secretary antibody (IgA). No correlation with tumour dissemination was observed. The role of Epstein-Barr virus leading to increase in IgA cannot be ruled out.

Significance of elevated IgA antibody levels in neonates withgastrointestinal conditions

Four groups of patients, 21 neonates with gastrointestinal anomalies, 8 with necrotizing enterocolitis, 5 with low anorectal anomalies and 15 with spina bifida were studied for the development of IgA and IgA subclass immunoglobulin levels. A highly significant increase in IgA levels (p less than 0.001) was seen in neonates with gastrointestinal anomalies and necrotizing enterocolitis while patients with low anorectal anomalies and spina bifida had normal or undetectable IgA levels. Estimation of IgA sub-class distribution in neonates with raised total serum IgA did not demonstrate any striking correlation between either IgA1 or IgA2 sub-classes and the clinical conditions but rather they reflected the level of total IgA. The levels if IgA, correlated closely with those of total IgA (r = 0.93) in all patients implying that in these patients total serum IgA is composed principally of IgA1 immunoglobulin.

IgA-antibody responses in the neonate following gastrointestinal surgery

IgA-antibody responses relative to other immunoglobulin classes were serially studied in 14 neonates undergoing gastrointestinal surgery and in a comparative group of 10 neonates undergoing surgery for neural tube defects. While IgM levels were raised postoperatively in gastrointestinal surgery patients as well in patients with neural tube defects the level of serum IgA following surgery was significantly higher in gastrointestinal patients (p less than 0.001) compared to neonates with neural tube defects. A close correlation between time of operation and an increase in IgA levels was observed. Changes in IgA antibody levels were independent of alteration in IgM and IgG levels.

The immunoglobulins in Hodgkin's disease

Serum immunoglobulin levels IgG, IgA and IgM have been investigated in 51 untreated patients with Hodgkin's disease and 102 control persons. In the patients with Hodgkin's disease the mean IgG and IgA level was significantly raised (P: 0·0001 for both). The mean IgM level in males was normal and was significantly increased (P: 0·0012) in females. The increase in IgA level was the most pronounced among the three immunoglobulins.