Humoral and cellular immune responses to Blomia tropicalis and concanavalin A-binding fractions in atopic patients

Blomia tropicalis, Dermatophagoides pteronyssinus and D. farinae are prevalent house dust mites. Concanavalin A-binding components derived from B. tropicalis (Bt-ConA extract) are highly immunogenic in allergic diseases. The aim of the present study was to evaluate the humoral and cellular immune responses to B. tropicalis in mite-sensitized patients. A total of 137 patients with allergic rhinitis with/without asthma and 109 non-atopic subjects were selected and analyzed by the skin prick test, and for total serum IgE and specific IgE levels to both Bt-total and Bt-ConA extracts, their proliferative response and cytokine (IFN-ã and IL-5) production by peripheral blood mononuclear cells (PBMC) stimulated with both extracts. Skin prick test showed that 70 percent of the patients were sensitized to Bt (Bt+) and similar levels of specific IgE to Bt-total and Bt-ConA extracts were demonstrable in Bt+ patients. Significant PBMC proliferation was observed in response to Bt-total extract in Bt+, but not in Bt- patients and non-atopic subjects (P < 0.001). Bt-ConA extract induced increased proliferative responses in all patient groups compared to medium alone (P < 0.05), but these responses were significantly decreased in the presence of the mannopyranoside ConA inhibitor (P < 0.05). Significant IFN-ã production was observed after Bt-ConA stimulation of Bt+ patients (P < 0.05), while Bt-total extract had no effect. IL-5 production was consistently detected in Bt+ patients after allergen-specific stimulation or with no stimulus, indicating that PBMC from allergic patients are prone to produce Th2 profile cytokines, spontaneously or inductively by allergen restimulation. These data showed that ConA-binding components isolated from B. tropicalis may contain relevant antigens that are involved in both humoral and cellular immune responses. However, without an additional purification procedure to eliminate the residual contamination with...

The effects of cyclophosphamide treatment on the pathogenesis of subgroup J avian leukosis virus (ALV-J) infection in broiler chickens with Marek's disease virus exposure

Studies were performed to determine the effects of Bcell suppression on the pathogenesis of Subgroup J avian leukosis virus (ALV-J) in broiler chickens. Neonatal chickens were treated with cyclophosphamide (CY) or PBS, and then infected with ALV-J (ADOL-7501) at 2 weeks of age. CY treatment induced B cell specific immunosuppression throughout the experiment confirmed by decreased bursal weight, intact lymphocyte mitogenetic activity stimulated by Con A and increased relative subpopulation of CD3-positive cells as measured by flow cytometry. Chickens in this experiment had Mareks disease virus exposure prior to three weeks of age as determined by the presence of lymphocytic infiltration and antibody. Virus neutralizing antibody against ALV-J was first observed at 6 weeks post-infection in some of the infected chickens in the PBS group. As expected, none of the chickens from the CY group and uninfected chickens developed virus-neutralizing antibody. The viremic status was measured by real time RT-PCR using SYBR green I dye. The percentage of viremic chickens was significantly higher, and more chickens had high titered viremia, in the CY treated group. No neoplastic foci consistent with ALVJ infection were observed in any of the experimental chickens. The frequency and intensity of viral antigen expression determined by immunohistochemistry was significantly higher in tissues from CY treated birds than those of PBS treated chickens at 3 weeks post-infection. This study showed that B cell specific immunosuppression with CY treatment in chickens resulted in increase in viremia and viral antigen load in tissues.

Efecto de dosis profiláctica de cloroquina sobre la respuesta linfoproliferativa a mitógenos / Effect of prophylactic doses of chloroquine upon mitogen-induced lymphoproliferative response

Se describe el efecto de la cloroquina administrada en dosis profiláctica de 300 y 600 mg base semanales, sobre la respuesta linfoproliferativa a los mitógenos fitohemaglutinina y concanavalina A. A todos los individuos se les realizó el estudio antes del tratamiento y a las 6 semanas de la administración de la droga. Se encontró una disminución estadísticamente significativa (p < 0,01) entre los valores obtenidos con ambos mitógenos, antes del tratamiento y a las 6 semanas, en el grupo que recibió la dosis a 600 mg base semanales. Con la concanavalina A también se observó este efecto, aunque en menor medida (p < 0,05), en el grupo que ingirió 300 mg base semanales

Suppression of Con A induced lymphocyte transformation by sera from filarial patients with clinical manifestations.

Reduced lymphocyte transformation to Wuchereria bancrofti microfilariae excretory-secretory antigen and Con A were observed in clinical filarial patients. Pre-incubation of normal human peripheral blood mononuclear cells with sera from filarial patients with clinical manifestations such as hydrocele and elephantiasis suppressed Con A induced responses. Effect of fractionated clinical filarial serum on Con A induced lymphocyte transformation showed that the inhibitory activity was associated with high molecular weight serum fraction.

Reactivity of Cryptococcus neoformans & Candida species with concanavalin A & blood grouping sera.

Forty strains of Cryptococcus neoformans, 30 of Candida albicans, 24 of C. parapsilosis and 10 strains each of C. tropicalis and C. (Torulopsis) glabrata were examined. A 0.2 per cent solution of concanavalin A (Con A) in phosphate buffered saline and commercial anti-A and anti-B blood grouping sera were used in the whole cell slide agglutination test. All the isolates of Candida species strongly reacted with Con A and over 90 per cent were agglutinated by anti-A and -B blood grouping sera. In contrast, except for one strain, Cryptococcus neoformans did not agglutinate with Con A or blood grouping sera. These findings suggest, on one hand, a fundamental difference in the sugar mosaic of the cell surface components of Cryptococcus neoformans and Candida species, and on the other, presence of similar antigenic determinant(s)/receptors on the cell surface of Candida species and human erythrocytes.

Agar plating technique for enumeration of IL-2 producing cells in human peripheral blood mononuclear leukocytes.

An agar plating technique for detection and enumeration of IL-2 producing cells from human peripheral blood mononuclear leukocytes (PBML) has been developed. This method is based on the principle that PHA-stimulated PBML, as effector cells, secrete interleukin 2 (IL-2) into soft agar containing mouse 3-day Con A blasts as IL-2 dependent responder cells. The IL-2 dependent Con A blasts proliferating around the IL-2 producing cells form colonies or clusters of cells and are easily visualized under a dissecting microscope. The development of IL-2 producing cells was optimum when 1 X 10(6) cells/ml PBML were stimulated with 2 micrograms/ml PHA-P for 4 hours, and when 2.5 X 10(5) cells were co-cultured with 6 X 10(6) Con A blasts in soft agar for 5 days. The average number of IL-2 producing cells in 10 normal healthy controls were 754 +/- 94 (mean +/- S.E.M.) cells/10(6) PBML. The numbers of IL-2 producing cells and the levels of IL-2 produced were highly correlated (r = 0.929). The subpopulation of lymphocytes in the colonies was shown to be mostly murine T-cells, since they were mostly Thy 1.2 positive, CD3 negative and surface immunoglobulin negative. This technique is very simple to perform and provides an accurate and straightforward means to enumerate IL-2 producing cells from human PBML in a variety of human immunologic disorders.

Lymphocyte response in mice infected with the Indonesian and Formosan strains of Schistosoma japonicum to concanavalin A, and to worm and egg antigens.

Cultures of splenocytes from mice infected with the Formosan and Indonesian strains of Schistosoma japonicum demonstrated a blastogenic response to concanavalin A (Con-A), adult worm antigen (SAA) and soluble egg antigen (SEA). The incorporation of tritiated thymidine was significantly greater for lymphocytes from mice infected with the pathogenic Indonesian strain than for lymphocytes from mice infected with the non-pathogenic Formosan strain in response to SAA; the responses also increased with duration of infection. The response to SEA, however, was only greater for the Indonesian strain, than that for the Formosan strain, at six weeks and the differences in response not statistically significant at five, seven, and nine weeks post-infection. The differences may have been associated with the number of worms developing in the mice since the adult worm recovery for the Indonesian strain was nearly twice that of recoveries from mice infected with the Formosan strain.