Iranian journal of immunology
Volume:7 Issue: 1, Winter 2010

Invariant natural killer cells (iNKT) are an important immunoregulatoryT cell subset. Currently several flow cytometry-based approaches exist for the identification of iNKT cells, which rely on using the 6B11 monoclonal antibody or a combination of anti-Vα24 and anti-Vβ11 antibodies. The aim of this study was to compare the ability of two flow cytometry-based methods for detecting the frequency of circulating iNKT cells. The frequency of iNKT cells was detected in the peripheral blood of 37 healthy adult donors by flow cytometry using the 6B11 antibody or a combination of anti-Vα24 and anti-Vβ11 antibodies. The frequency of iNKT cells detected by 6B11 antibody or by combination of anti-Vα24 and anti-Vβ11 antibodies was significantly different (0.54% vs. 0.31%, respectively, p<0.001) but the values were highly correlated (Spearman r = 0.742, p<0.0001). The results ofthis study indicate that different combinations of mAbs detect different frequencies ofperipheral blood iNKT cells and a consensus in the field needs to be established to allowbetter assessment of iNKT-related studies and suggest using different methods foraccurate identification of iNKT cells.

Interaction between killer cell immunoglobulin-like receptors (KIR) and human leukocyte antigen (HLA) class I molecules is important for regulation of naturalkiller (NK) cell function. The aim of this study was to investigate the impactof compound KIR-HLA genotype on susceptibility to acute leukemia. Cohorts of Iranian patients with acute myeloid leukemia (AML; n=40) and acute lymphoid leukemia (ALL; n=38) were genotyped for seventeen KIR genes and their three major HLA class I ligand groups (C1, C2, Bw4) by a combined polymerase chainreaction–sequence-specific primers (PCR-SSP) assay. The results were compared withthose of 200 healthy control individuals. We found a significantly decreasedfrequency of KIR2DS3 in AML patients compared to control group (12.5% vs. 38%,odds ratio=0.23, p=0.0018). Also, the KIR3DS1 was less common in AML group thancontrols (27.5% vs. 44.5%, p=0.0465, not significant after correction). Other analysesincluding KIR genotypes, distribution and balance of inhibitory and activatingKIR+HLA combinations, and co-inheritance of activating KIR genes with inhibitoryKIR+HLA pairs were not significantly different between leukemia patients and thecontrol group. However, in AML patients a trend toward less activating and moreinhibitory KIR-HLA state was observed. Interestingly, this situation was not found inALL patients and inhibition enhancement through increase of HLA ligands and inhibitorycombinations was the main feature in this group. Our findings maysuggest a mechanism for escape of leukemic cells from NK cell immunity.

Unrestricted somatic stem cells (USSC) are cord blood stem cells that have been considered as candidates for the regulation of immune responses. Therefore, potential exists for their use in the suppression of immune response after transplantation surgery. The aim of this study was evaluation of the effect of USSC on mixed lymphocyte reaction (MLR) as a model for graft rejection. USSC and mesanchymal stem cells (MSC) were isolated and cultured from cord blood and bone morrow, respectively. The immunophenotypes of USSC and MSC were evaluated by flow cytometery and USSC and MSC were co-cultured with peripheral blood lympho-cytes (PBL) in an MLR to evaluate the immunomodulatory effect of these cells as a percentage of the control response. Current study demonstrated that prolifera-tion of lymphocytes in the MLR was decreased after treatment with USSC, in a similar fashion to that seen with MSC. It can be concluded that USSC have simi-lar regulatory effects as MSC on the MLR, which can be used as an indicator for poten-tial organ rejection after transplantation. Therefore, the immunregulatory effect of these cells could be used in the clinic during organ transplantation and in the management of autoimmunity.

Unrestricted somatic stem cells (USSC) are cord blood stem cells that have been considered as candidates for the regulation of immune responses. Therefore, potential exists for their use in the suppression of immune response after transplantation surgery. The aim of this study was evaluation of the effect of USSC on mixed lymphocyte reaction (MLR) as a model for graft rejection. USSC and mesanchymal stem cells (MSC) were isolated and cultured from cord blood and bone morrow, respectively. The immunophenotypes of USSC and MSC were evaluated by flow cytometery and USSC and MSC were co-cultured with peripheral blood lympho-cytes (PBL) in an MLR to evaluate the immunomodulatory effect of these cells as a percentage of the control response. Current study demonstrated that prolifera-tion of lymphocytes in the MLR was decreased after treatment with USSC, in a similar fashion to that seen with MSC. It can be concluded that USSC have simi-lar regulatory effects as MSC on the MLR, which can be used as an indicator for poten-tial organ rejection after transplantation. Therefore, the immunregulatory effect of these cells could be used in the clinic during organ transplantation and in the management of autoimmunity.

Pandemic flu had at least two waves in Iran. Knowing how many of the general population were already exposed to this infection has a major impact on national preventive measures. As of December 30, 2009, a total of 3672 confirmed casesof human infection with a novel Influenza A (2009 H1N1) virus had been reported inIran with 140 deaths. In this study we aim to measure, as a pilot study, theseroprevalence of positive antibody titer (humoral immunity) against 2009 H1N1 virusin Iranian population in Shiraz, Southern Iran. Through cluster random samplingof families residing in Shiraz, 2553 subjects were selected and after a medical interviewblood samples were taken and checked for polyclonal antibody against 2009H1N1 antigen using hemagglutination inhibition assay. An antibody titer of more than1:40 dilution was considered positive. Data were analyzed considering the demographiccharacteristics of the population and were compared among different age groups. 1504 (58.91%) samples were tested positive for the presence of polyclonal antibody against 2009 H1N1 virus. The prevalence of positive titers were significantly higher in 60 to 64 years old group and significantly lower in 20 to 24 years old group (p<0.05). Data did not differ based on other demographic characteristics or the history of flu like illnesses in the past 6 months. High seroprevalence of antibody against 2009 H1N1 in the sera of our subjects describes either a high level of preexisting immunity against H1N1 in Iranian population or a high rate of asymptomaticinfection in our area compared to other countries.

Protective immune responses induced in the majority of people infected with Mycobacterium tuberculosis enable them to control TB infection. Theaim of this study was to investigate CD56 and CD16 positive peripheral blood mononuclearcells (PBMCs) and leukocyte subsets from multi-drug resistant pulmonary tuberculosis (MDR-TB)، and compare them with nonresistant (NR) TB patients and healthycontrols. 13 MDR-tuberculosis patients، 20 NR-TB individuals and 40healthy subjects were included. Peripheral blood mononuclear cells were double stainedwith fluorochrome conjugated antibodies against CD56 and CD16 cell surface markers. The phenotype of positive cells was then analyzed by flow cytometry and the percentages of CD56+ CD16+، CD56- CD16+، CD56dimCD16+/-، and CD56brightCD16+/- subsets were calculated. There was a significant decline in the percentage ofCD56+CD16+ lymphocytes in both MDR and NR-TB patients compared with healthycontrols. We also observed lower proportions of CD56dim/brightCD16+ in addition tohigher percentages of CD56dim/brightCD16- subsets in all TB patients (p≤0. 05). In MDRTB، our findings demonstrated a distinct phenotypic feature with increased levels ofCD56brightCD16- in comparison with both NR-TB and healthy subjects. Considering the function of CD56/CD16 expressing cells in TB، we suggest that phenotypic characteristics of PBMCs in MDR-TB may correlate with their status of drug resistance and probably with their high mortality rates.

Mycobacterium tuberculosis lipid antigens take part in pathogenicity of the bacterium but the response of monocytes/macrophages to these antigens in tuberculosis is not well known. The aim of current investigation was to study the M. tuberculosis lipid antigens in tuberculosis pathogenesis. In the present studyM. tuberculosis lipid antigens were extracted. Monocytes and macrophages from multidrug- resistant tuberculosis (MDR-TB), TB patients, asymptomatic healthy individualswith positive tuberculin skin test positive and healthy individuals with negative tuberculinskin test were collected using magnetic cell sorting. The cells were stimulated by M.tuberculosis total lipid antigens and IL-12 and IL-10 in their supernatants were measuredby enzyme-linked immunosorbent assay. The IL-12 production by monocytesin response to M. tuberculosis total sonicate antigens in the MDR-TB patients didnot show a considerable difference with the PPD positive healthy subjects, whereas inthe active TB patients, IL-12 levels significantly decreased (p<0.05). IL-10 productionby monocytes in TB patients in response to total lipid antigens showed a significant increase in comparison to MDR-TB patients and healthy individuals. In the MDR-TB patients, IL-10 and IL-12 production by monocytes in response to M. tuberculosis lipid antigens are similar to the healthy subjects.