Purification and characterization of novel toxin produced by Vibrio cholerae O1

Vibrio cholerae WO7 (serogroup O1) isolated from patients with diarrhea produces an extracellular toxin despite the absence of ctx, zot, and ace genes from its genome. The toxin elongates Chinese hamster ovary cells, produces fluid accumulation in ligated rabbit ileal loops, and agglutinates freshly isolated rabbit erythrocytes. Maximal production of this toxin (WO7 toxin) was seen in AKI medium with the pH adjusted to 8.5 at 37 degrees C under shaking conditions. We purified this toxin to homogeneity by sequential ammonium sulfate precipitation, affinity chromatography using a fetuin-Sepharose CL-4B column, and gel filtration chromatography, which increased the specific activity of the toxin by 1.6 x 10(6)-fold. The toxin is heat labile and sensitive to proteases and has a subunit structure consisting of two subunits with molecular masses of about 58 and 40 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Agglutination of GM1-coated sheep erythrocytes by toxin suggests that GM1 might be the physiologic receptor for WO7 toxin on the enterocytes. An immunodiffusion test between the antiserum raised against the purified WO7 toxin and the purified toxin gave a well-defined precipitation band. In the immunoblot assay, two bands were observed in the 58- and 40-kDa region. At the same time, antiserum against WO7 toxin failed to show any cross-reactivity with cholera toxin or Escherichia coli heat-labile toxin (LT1) in an immunodiffusion test or immunoblot assay. The enterotoxic activity of WO7 toxin could be inhibited by antiserum against purified WO7 toxin. Our results indicate that WO7 toxin is structurally and functionally distinct from other cholera toxins and that the enterotoxic activities expressed by WO7 toxin appear to contribute to the pathogenesis of disease associated with V. cholerae O1 strains.

Protective efficacy and immunogenicity of Vi-porin conjugate against Salmonella typhi

A conjugate vaccine against Salmonella typhi was prepared by covalently binding capsular polysaccharide (Vi) with porin, both isolated from S. typhi. First, Vi and porins were extracted. The Vi was purified from S. typhi Ty2. The purified Vi conformed to the requirements of the World Health Organization. Porins were purified from S. typhi 0901. The Vi was bound to the porins by a heterobifunctional cross-linking reagent, N-succinimidyl-3-(2-pyridyl dithio)-propionate (SPDP). After preparing the Vi-porin conjugate, its protective ability and immunogenicity were studied in mice following systemic immunization. The results showed that the conjugate is 6.5-fold more protective than Vi alone against S. typhi. The mice immunized with conjugate elicited higher anti-Vi antibody (IgG) levels (P < 0.01) than the mice immunized with Vi alone. Anti-porin antibodies were also induced by the conjugate. To study the mucosal immune responses, secretory IgA (sIgA) in the intestinal fluid was measured. Conjugate-immunized mice showed the induction of sIgA as compared to Vi alone. The results showed that when Vi is bound to porins, both isolated from same organism, the resultant conjugate induced both systemic and mucosal immune responses and provided better protection against S. typhi than Vi alone.

Identification of copper-zinc superoxide dismutase gene from enteroaggregative Escherichia coli

We describe here the identification of sodC gene from enteroaggregative Escherichia coli (EAggEC). A 294 bp gene-specific fragment was amplified from the organism by DNA as well as RT-PCR using primers from bacterial sodC sequences. The metal co-factor present in the protein was confirmed by running samples in native gels and inhibiting with 2 mM potassium cyanide. However, the nonpathogenic E. coli possesses the gene but does not express it. Thus, the presence of copper-zinc superoxide dismutase encoded by sodC was demonstrated for the first time in EAggEC, which means it could be a novel candidate for a virulence marker.

Serial plasma fibronectin levels in pre-eclamptic and normotensive women

OBJECTIVE

Endothelial cell damage has been put forward as an underlying factor for development of pre-eclampsia. This study was carried out to see if fibronectin, which is a marker of endothelial damage, could be used as a marker of pre-eclampsia.

METHODS

A longitudinal study was conducted on 100 normotensive primigravidae registered before 20 weeks of gestation. These subjects were followed until delivery and three blood samples were collected, first at registration, i.e. before 20 weeks, second around 28 weeks and third at 36 weeks or later till delivery. Fibronectin levels were assayed by ELISA and women observed for any signs of pre-eclampsia.

RESULTS

Fourteen subjects developed pre-eclampsia. Fibronectin levels were observed to rise as pregnancy advanced but the rise was significantly higher in subjects who developed pre-eclampsia. The fibronectin levels were also significantly higher in these 14 subjects even in the first sample, i.e. before 20 weeks of gestation when compared with normotensive subjects (P < 0.01).

CONCLUSIONS

Fibronectin levels could be used as an early valuable biomarker for the development of pre-eclampsia.

Evaluation of serum creatine kinase as a diagnostic marker for tubal pregnancy

Forty women comprising of 20 each in study and control groups had their serum creatine kinase (CK) estimated. The study subjects were proven cases of ectopic pregnancy and the controls were either medical termination of pregnancy seekers or antenatal cases matched for gestational age and with a confirmed intrauterine pregnancy. Total serum creatine kinase levels were found to be significantly higher in the study group i.e. 34.15 +/- 1.17 IU/L compared to the controls 18.72 +/- 1.25 (p < 0.001). Creatine kinase is estimated routinely in cardiac patients even on an emergency basis. Our findings indicate that when in doubt the test could be used as a marker for the diagnosis of ectopic pregnancy.

Increased plasma nitrite level in cardiac failure

Increased Plasma Nitrite Level in Cardiac Failure. Nitric oxide is implicated in the pathogenesis of cardiac failure. Plasma nitrite level (an end product of nitric oxide metabolism) is studied in 15 patients of chronic rheumatic valvular heart disease with myocardial contractile dysfunction and cardiac failure (Group I), 15 patients of chronic rheumatic valvular heart disease with similar valvular lesions, normal myocardial contractile function and without cardiac failure (Group II) and 15 healthy controls (Group III). Patients in Group I had higher nitrite level (242.2+/-31.7 n m) compared to Group II (142.6+/-24.4 n m) and Group III (102.7+/-15.9 n m). Among the patients with rheumatic heart disease, increasing nitrite level correlated significantly with worsening of contractile function [Nitrite v End systolic volume/Body surface area (T(xy.z)=0.23), Nitrite v End systolic dimension/Body surface area (T(xy.z)=0.32), Nitrite v left ventricular ejection fraction (T(xy.z)=-0.24), Nitrite v tricuspid annular plane systolic excursion (T(xy.z)=-0. 29)] and worsening New York Heart Association (NYHA) functional class (r(s)=0.5). We conclude that plasma nitrite, a stable end product of nitric oxide metabolism is increased in patients of rheumatic valvular heart disease with cardiac failure, suggesting increased nitric oxide production. Increased level of nitric oxide might be playing a significant role in myocardial contractile dysfunction and alteration of vascular response in cardiac failure.

A monoclonal antibody-based test system for detection of Entamoeba histolytica-specific coproantigen

BACKGROUND

Diagnosis of amebiasis based on stool microscopy or demonstration of anti-amebic antibodies has limitations. A diagnostic system based on demonstration of the parasite product in clinical specimens holds promise.

METHODS

Murine monoclonal antibodies were developed against an Entamoeba histolytica-specific coproantigen. A monoclonal antibody (MoAb) 3D10 was employed in a double-antibody sandwich microELISA system for the detection of amebic coproantigen in fecal specimens. The system was evaluated in three groups of subjects: 63 patients with intestinal amebae, 27 with non-amebic parasitosis, and 57 apparently healthy controls.

RESULTS

The MoAb 3D10 belonged to IgG1 isotype and recognized three antigens, with mol. wt. 36, 25 and 17 kDa in the crude extract of E. histolytica (HM1-IMSS), and an amebic coproantigen with MW 36 kDa in the stool supernatant from patients with intestinal amebae. The coproantigen was detected in the stool eluates of 56 (89%) patients with intestinal amebae and in none of the stool eluates from other subjects, thereby giving this system a sensitivity of 89% and specificity of 100% for the detection of intestinal amebae.

CONCLUSIONS

This monoclonal antibody recognizes as intact epitope on the E. histolytica-specific coproantigen. The validity of the MoAb-based microELISA system needs to be established.

Clinical significance of carcinoembryonic antigen in colorectal malignancy

Carcinoembryonic antigen (CEA) assay was performed in 40 patients of histologically proven colorectal carcinoma. The overall incidence of positivity was 72.5%. The incidence increased from 40% in Duke's A stage to 84.6% in Duke's C stage. Similarly the mean CEa levels also increased as the disease advanced i.e. 4.96 ng/ml, 8.07 ng/ml and 12.7 ng/ml in Duke's A, B and C respectively. Cancer with poor prognosis i.e. poorly differentiated and colloid carcinoma, had significantly less rise in CEA values (P < 0.05) as compared to well differentiated carcinoma. There was no relation of CEA values with the gross appearance of the tumour and lymph node involvement. CEA level came down in all the patients after surgery. Based on the postoperative CEA estimation, complete tumour clearance had been achieved in 86.2% of patients.

Inhibition of apoptosis by ionomycin and zinc in peripheral blood mononuclear cells (PBMC) of leprosy patients

PBMC from tuberculoid (BT/TT) and lepromatous leprosy (BL/LL) leprosy patients showed spontaneous apoptosis when cultured in the absence of mitogen for 24 h, which was inhibited by anti-tumour necrosis factor-alpha (TNF-alpha) antibodies. Apoptosis was also inhibited by ionomycin and zinc, which also increased IL-2 and decreased TNF-alpha production. The increase in IL-2 production suggests a mechanism whereby dietary supplements with zinc might alter the cell-mediated immunity response in leprosy patients.

Characterization of Giardia lamblia groups A and B from North India by isoenzyme and random amplified polymorphic DNA analysis

Giardia lamblia (syn. G. intestinalis) infection in young adults leads to acute/chronic diarrhea in some individuals and is asymptomatic in others. Recently, G. lamblia strains have been characterized as group A (symptomatic) and group B (asymptomatic or control) by advanced isoenzyme and molecular biology studies. In the present brief pilot study, ten G. lamblia isolates obtained from five symptomatic (group A) and five asymptomatic (group B) persons were characterized by isoenzyme and random amplified polymorphic DNA (RAPD) analysis. Isoenzyme analysis demonstrated remarkable homogeneity in seven enzyme patterns, the exception, being that of phosphoglucomutase, for which two zymodemes (I and III) were observed. In contrast, RAPD analysis showed homogeneity for eight primers; exceptions were two primers, A02 and B05, which separated group A G. lamblia isolates into two rapdemes (A(R1) and A(R2)) and group B G. lamblia isolates into four rapdemes (B(R1), B(R2), B(R3) and B(R4)). Further phenetic analysis showed average genetic distances of 0.105 within group A and 0.121 within group B G. lamblia isolates according to Jaccord's distance scale, which suggests that both lineages appear to consist of a range of variants with no significant (P < 0.05) genetic diversity. The two techniques demonstrated a positive association with regard to differentiation between group A and group B G. lamblia isolates. These very preliminary results indicate that RAPD analysis could be a potentially useful substitute for isoenzyme analysis.

Spontaneous apoptosis in peripheral blood mononuclear cells of leprosy patients: role of cytokines

Peripheral blood mononuclear cells from leprosy patients underwent spontaneous apoptosis upon culture for 24 h. The apoptosis was inhibited by anti-TNFalpha antibodies and to a certain extent by anti-IL-1alpha and IL-6, thus showing that T(H)2-type cytokines (mainly TNFalpha) are responsible for inducing apoptosis. This cytokine-mediated apoptosis could be inhibited by ionomycin and zinc, thereby suggesting that these metal ions can be used to decrease the levels of these inflammatory cytokines in various diseases.

Comparative evaluation of the inflammatory mediators in patients undergoing laparoscopic versus conventional cholecystectomy

BACKGROUND

Injury induces systemic inflammatory response. The degree of response is proportionate to the trauma.

METHODS

Patients with ultrasound-proven gall stones posted for operation were randomized into two groups. Laparoscopic cholecystectomy was performed in one group while the other group underwent conventional cholecystectomy. Peripheral venous blood samples for inflammatory mediators, namely tumour necrosis factor, C-reactive protein, oxygen release from monocytes and polymorphonuclear leucocytes were drawn 1 day before surgery and repeated on the first and third days after surgery. Partial pressure of arterial oxygen was also measured in both groups. Only patients who met selection criteria and had uncomplicated postoperative courses were included in the study. There was a total of 40 patients for the final analysis, 20 in each group.

RESULTS

There was no significant difference (P > 0.1) in age, sex or body mass index in both groups of patients. The level of all of the inflammatory mediators was elevated on the first postoperative day; however, the elevation was significantly less following laparoscopic cholecystectomy compared to conventional cholecystectomy (P < 0.01). Although the values came down on the third postoperative day, they remained above the respective controls. Postoperative hypoxaemia was significantly more in patients of conventional than laparoscopic cholecystectomy (P < 0.001).

CONCLUSIONS

Trauma-induced inflammatory response is significantly less following laparoscopic cholecystectomy compared to conventional cholecystectomy. It appears to be related to degree of trauma.

The role of oxidized HDL in monocyte/macrophage functions in the pathogenesis of atherosclerosis in Rhesus monkeys

The effect of oxidative modification of high-density lipoprotein (HDL) was assessed by incubation of normal HDL (obtained from Rhesus monkeys fed a stock diet) with 5 microM CuSO4 at 37 degrees C for 12 h/24 h. The physicochemical properties of oxidized-HDL (Ox-HDL) were found to be affected in terms of lipid peroxidation, as observed by the increased level of thiobarbituric acid reactive substances (nmol MDA/mg HDL protein). The biological properties of HDL were altered, since a decrease in the efflux of free cholesterol into the medium was found in the presence of Ox-HDL24h compared with normal HDL (N-HDL). The binding, uptake and degradation of 125I-LDL by macrophages increased in the presence of Ox-HDL24h. The activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione-peroxidase) was reduced in monocytes in the presence of Ox-HDL. However, in the presence of N-HDL, the levels of antioxidant enzymes were maintained at a higher level than in the control (in the absence of HDL) monocytes. Furthermore, the number of monocytes adhered to aortic endothelium were found to be increased in the presence of Ox-HDL. These findings suggest that HDL is susceptible to oxidative modification. Since the parameters selected in the present study are involved in the pathogenesis of atherosclerosis, it can be postulated that the in vivo protection of HDL in atherosclerosis can be reversed in the circumstances in which HDL undergoes oxidative modification like low-density lipoprotein (LDL).

Involvement of signal transduction pathways in Salmonella typhimurium porin activated gut macrophages

Many membrane proteins are implicated in the regulation of cell functions by triggering specific signaling pathways. Porins are known potential modulators of cell proliferation and differentiation. We explored the possible involvement of this protein in signal transduction pathways in mouse gut macrophages. In the present work we have shown that porins can trigger signal transduction in mouse macrophages infected with S. typhimurium. Activation of macrophages by porins results in an increase in inositol trisphosphate and intracellular Ca2+ mobilization. There is a translocation of protein kinase C to the membrane which is accompanied by nitric oxide release within the macrophages. This effect is the outcome of the expression of nitric oxide synthase, which is dependent on Protein kinase C. Further, we observed that there is an increased binding of the porins on macrophages infected with S. typhimurium which results in activation of macrophages and triggering of specific signaling pathways. These results indicate that porins induce the production of nitric oxide via a protein kinase C dependent pathway. Nitric oxide plays a fundamental role in macrophage effector function where it has both communication and defensive function.

Immunological defect in leprosy patients: altered T-lymphocyte signals

The early events of activation were studied in paucibacillary (TT/BT) and multibacillary (BL/LL) leprosy patients by stimulation of their lymphocytes with mitogenic agents (calcium ionophore A23187/PMA) and Micobacterium leprae antigen (PGL-1). Maximum proliferation in response to PMA/A23187 and PGL-1 was observed in the BT/TT patients and the control group, respectively. Inositol triphosphate (IP3) and calcium were constitutively elevated in BT/TT and LL/BL patients. PMA/A23187 caused an increase in both IP3 and [Ca2+]i in BT/TT patients and controls. PGL-1 marginally increased IP3 levels in BT/TT patients. In the LL/BL patients, although PMA/A23187 increased IP3 levels, but no change was seen in [Ca2+]i, PGL-1 had no effect. Protein kinase C levels were seen to be associated with particulate fractions in BT/TT patients and were found to increase further in response to PMA/A23187. PGL-1 did not increase translocation of protein kinase C in controls or LL/BL patients. A preactivated and sensitised state of T-lymphocytes was observed in BT/TT patients, responsive to antigen and mitogens, whereas the cells of LL/BL patients were unresponsive to PGL-1. The altered signal transduction events characterised in the MB patients thus correlate well with the anergic state of their cells.

Superantigen-induced T cell responses in acute rheumatic fever and chronic rheumatic heart disease patients

CD4+ and CD8+ T cells from healthy donors, acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD) patients responded variably to a superantigen from Streptococcus pyogenes--Streptococcal pyrogenic erythrogenic toxin A (SPE-A). In vitro culture of CD4+ T cells from ARF patients (CD4-ARF) with SPE-A exhibited a Th1 type of response as they produced high levels of IL-2, while CD4+ T cells from CRHD patients (CD4-RHD) secreted IL-4 and IL-10 in large amounts, i.e. Th2 type of cytokine profile. The skewing of human CD4+ T cells (in response to SPE-A stimulation) to Th1 or Th2 type reflects the role of the two subsets in a disorder with differing intensities at the two extremes of the spectrum. Moreover, the anergy induction experiments revealed that CD8-ARF and CD8-RHD undergo anergy (to different extents), whereas CD4+ T cells do not, in response to re-stimulation by SPE-A. These results initially demonstrate that both CD4+ and CD8+ T cells respond differentially to SPE-A, and hence it is an important observation with respect to the pathogenesis of ARF/CRHD. Anergy in CD8+ T cells in the presence of SPE-A in vitro goes a step further to show the clinical relevance of these cells and their possible role in suppression of the disease.

Aural cholesteatoma: role of tumor necrosis factor-alpha in bone destruction

HYPOTHESIS

The bone destruction in cholesteatoma is multifactorial. This study was undertaken to define the role of tumor necrosis factor-alpha (TNF-alpha) in bone destruction associated with cholesteatoma.

BACKGROUND

Tumor necrosis factor-alpha is an important inflammatory cytokine secreted by activated macrophages. It stimulates keratinocytes as an autocrine growth regulator. Few authors have localized TNF-alpha in aural cholesteatoma. An attempt was made in this study to show a correlation between TNF-alpha and cholesteatoma associated bone destruction by localizing TNF-alpha in cholesteatoma and measuring its serum level.

METHODS

Serum TNF-alpha levels were measured in 20 patients with cholesteatoma of temporal bone and histochemical staining was used to localize TNF-alpha in pathologic tissue excised at surgery.

RESULTS

Serum TNF-alpha levels in patients with cholesteatoma were significantly higher than in controls. In addition, TNF-alpha levels in patients with bone destruction were higher than in those without bone destruction. However, there was no correlation between age of the patient and serum TNF-alpha levels. The TNF-alpha was localized in various layers of cholesteatoma epithelium using indirect immunoperoxidase staining.

CONCLUSION

TNF-alpha is one of the cytokines produced by cholesteatoma that may be an important mediator of bone destruction associated with cholesteatoma. TNF-alpha has been localized in various layers of cholesteatoma and exerts a locally destructive effect on bone. Serum TNF-alpha levels are related to the extent of bone destruction.

Immune effector responses to an excretory-secretory product of Giardia lamblia

The prior immunisation of mice with purified excretory-secretory product (ESP) led to a complete failure of Giardia lamblia colonisation following challenge inoculation of these animals with trophozoites. The prior immunisation of mice with ESP resulted in a significant stimulation of local immunity as evidenced by a significant enhancement of T helper/inducer activity along with a significant increase in immunoglobulin A-bearing cells. Further, the presence of anti-ESP antibodies in the serum of immunised as well as immunised-challenged animals indicated the stimulation of the systemic lymphoid system. This suggests that the ESP is highly immunogenic and it could be one of the major antigens of G. lamblia responsible for protection against the infection.

Quantitative enzymuria following aorto-renal angiography

Quantitative estimation of urinary enzymes has been advocated as a more sensitive marker than conventional renal function tests to assess radio-contrast media induced nephrotoxicity. We studied 27 subjects with normal renal functions who underwent abdominal aortography for varied indications. Among these, 8 also required selective renal arteriography and 3 underwent arch aortography in addition. Sodium iothalamate was used as a radio-contrast medium and the average amount injected was 73 ml (45 to 120 ml) per subject. Standard renal function assessment including urinalysis, 24 hour urinary protein excretion, creatinine clearance done both before and after aortography did not show any significant alteration. Urinary excretion of tubular enzymes including leucine aminopeptidase (LAP), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT) and maltase (MAL) was estimated before and 2, 24 and 48 hours after aortography. All enzymes showed a significant rise at 2 hours. Urinary excretion of LAP, ALP and GGT peaked at 24 hours after aortography without a further change in MAL levels. Enzymuria returned to baseline values 48 hours following the procedure. It is concluded that an increase in the urinary excretion of the brush-border enzymes within 24 hours of contrast media administration may suggest an early nephrotoxicity.

Comparative evaluation of methods of malaria parasite density determination in blood samples from patients & experimental animals

Three methods for the quantitation of parasitaemia in malaria were compared with the standard method for ascertaining the accuracy in patients, Plasmodium berghei infected mice and P. knowlesi infected Rhesus monkeys. Technique I, where parasitaemia was calculated from the number of PRBCs in 10,000 RBCs in thin blood film and the total RBC count of the host, was used as the standard. Technique II, where parasitaemia was calculated based on the number of PRBCs per WBC and average total WBC count (8000/microliter), was least accurate. Technique IV, where parasitaemia was calculated from the number of PRBCs per oil immersion field (OIF) of microscope and the estimated amount of blood in one OIF of a thick smear, was most accurate when parasitaemia was low as in malaria patients and experimental animals with < 1 per cent parasitaemia. In mice with moderate parasitaemia (5-10%) and in falciparum malaria cases (with 3-7% parasitaemia) also technique IV was most accurate. In both animal models showing high (15-25%) and in monkeys with moderate parasitaemia, technique III based on the number of PRBCs per WBC and actual total WBC count, was the most accurate. Thus, technique IV being simpler and cost effective, with standardization of the amount of blood used in making a thick smear, may be used routinely for quantitation of parasitaemia.

Reactive oxygen intermediates and reactive nitrogen intermediates in copper intrauterine device users

The mechanism of action of copper in copper intrauterine devices (Cu IUD) as an antimicrobial agent is not well understood. Copper and iron are supposed to be responsible for release of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI), which are very active in the presence of infection. The copper in a copper IUD could be responsible for limiting pelvic inflammatory disease. The present study was composed of 20 IUD seekers in whom ROI and RNI were studied before insertion of Cu IUD and then at 1, 4, and 12 weeks afterward. ROI showed a rise after insertion, whereas RNI showed a steady decline. Hence, it is presumed that the rise in ROI could be responsible for both the bactericidal effect of Cu IUD and also for the fall in RNI.

Role of serum in regulating the Entamoeba histolytica cell cycle: a flowcytometric analysis

To identify stage-specific molecules that might be important in pathogenicity, we focused on synchronizing Entamoeba histolytica HM1:1MSS axenic cultures by serum deprivation. By growing trophozoites in medium containing 2% serum for 16 h and then replacing with complete medium, we found that most of the trophozoites were in the G0/G1 phase of the cell cycle. Subsequently, the distribution of trophozoites in G0/G1, S and G2/M phases was studied for up to 24 h and it was observed that after 8 h, the trophozoites began to come out of the quiescent G0/G1 phase and the S and G2/M populations increased, indicating that certain serum factors regulate induction of cell division. It will be important to investigate these factors to find serum substitutes for cultivation media.

Alterations in early biochemical events following T cell activation in leprosy patients

The early events of activation and cytokine profiles (IL-2, 4, and 6) were studied in lymphocytes of paucibacillary (TT/BT) and multibacillary (BL/LL) leprosy patients after stimulation with PMA/A23187 and Mycobacterium leprae antigen (PGL-1). Lymphocytes from BT/TT patients showed proliferation in response to both PMA/A23187 and PGL-1 compared to BL/LL. The levels of early activation signaling molecules such as IP3, calcium, and protein kinase C (PKC) in the particulate fraction were found to be elevated in BT/TT and BL/LL patients and showed a further significant increase after stimulation with PMA/A23187 in BT/TT patients. PGL-1 marginally increased the IP3 levels in BT/TT patients, whereas in BL/LL patients, it had no effect. The levels of IL-2 were enhanced in lymphocytes of BT/TT leprosy patients and were further augmented by PPD and PGL-1, while the levels of IL-4 and IL-6 were increased in LL/BL lymphocytes and further augmented by PGL-1. Thus PGL-1 seems to be a major culprit in inducing the TH2-type cytokine response observed in lepromatous leprosy patients.

Characterization of lymphocytic subsets and cytokine production in gastric biopsy samples from Helicobacter pylori patients

BACKGROUND

This study characterized the phenotypic subsets of isolated gastric lymphocytes and the cellular immune response in cultured gastric biopsy specimens.

METHODS

Endoscopy specimens from 40 Helicobacter pylori-positive and 40 H. pylori-negative patients were studied. a) Isolated gastric lymphocytes were analysed for CD4+, CD8+ T-lymphocyte subsets, activated T cells, and natural killer cells on a fluorescence-activated cell sorter, using monoclonal antibodies. b) The supernatant of cultured gastric biopsy specimens were assayed for interleukin (IL)-2, IL-4, and IL-6 levels.

RESULTS

In H. pylori-positive patients there was (a) a decrease in CD4+/CD8+ T cells, no change in activated T cells, and an increase in natural killer cells, and (b) no change in IL-2 levels and a significant increase in IL-4 and IL-6 levels.

CONCLUSIONS

There is an increase in CD8+ lymphocytes and natural killer cells, and the observed increase in IL-4 and IL-6 might be important in H. pylori-associated gastritis.