Evaluation of an albumin-binding domain protein fused to recombinant human IL-2 and its effects on the bioactivity and serum half-life of the cytokine

Background: Cancer immunotherapy is a promising strategy for cancer treatment. In this strategy, the immune system is triggered to destroy cancer cells. IL-2 is an important factor in passive cancer immunotherapy that helps modulating some important immune functions. One of the IL-2 limitations is low serum half-life; therefore, repetitive high doses of the injections are required to maintain effective concentrations. High-dose IL-2 therapy results in severe side effects; thus, improvement of its serum half-life would provide therapeutic benefits

Methods: We have investigated a strategy that is able to utilize an albumin-binding domain [ABD] from streptococcal protein G. In this strategy, the fusion protein ABD-rIL-2 binds to serum albumin, which results in improvement of the IL-2 serum half-life. PET26b+ plasmid was used as an expression vector, which encoded rIL-2 and ABD-rIL-2 both fused to pelB secretion signal under the control of the strong bacteriophage T7 promoter. The constructs were expressed in E. coli Rosetta [DE3] and secreted into the periplasm

Results: The analysis of in vitro bioactivity proved that the fusion of ABD to rIL-2 does not interfere with its bioactivity. ABD-rIL-2 fusion protein indicated higher serum half-life compared to rIL-2, when it was tested in the BALB/c mice

Conclusion: The current study provides an alternative strategy to extend the half-life and improve pharmacokinetic properties of rIL-2 without reducing its bioactivity in vitro

Selective immunoglobulin a deficiency in Iranian blood donors: prevalence, laboratory and clinical findings

Selective deficiency of immunoglobulin A [IgA] is the most frequent primary hypogammaglobulinemia. As some IgA-deficient patients have IgA antibodies in their plasma which may cause anaphylactic reactions, blood centers usually maintain a list of IgA-deficient blood donors to prepare compatible blood components. In this study we determined the incidence of selective IgA deficiency [SIgAD] in normal adult Iranian population. 13022 normal Iranian blood donors were included in this study. The assay which we used was adapted to the manual pipetting system and ELISA reader was used for screening. Other classes of immunoglobulins [G, M], as well as secretory IgA and IgG subclasses were tested in IgA deficient cases by ELISA. SPSS was used for statistical analysis. Among 13022 studied cases, 11608 blood donors were males [89.14%] and 1414 were females [10.86%]. Their mean [ +/- SD] age and weight were 38.5 +/- 11 years and 82 +/- 12 Kg respectively. Twenty of the screened samples were found by means of ELISA to be IgA-deficient [less than 5mg/dl], [frequency; 1:651]. The data could indicate a compensation for IgA deficiency by serum IgM in one of our IgA deficient cases [Patient 5]. We observed a correlation between IgG3 and serum IgA in deficient cases [r=0.498, P=0.025]. Our results indicate that in present study the prevalence of S IgA D is in agreement with data from other Caucasians populations [from 1:300 to 1:700]. In conclusion, Selective IgA Deficiency could be almost asymptomatic in most cases in general population. Our study suggests that; due to high frequency of IgA deficiency in Iran, it seems necessary to measure IgA levels for every blood donor and blood recipient to find IgA deficient cases

CD40 ligand expression on stimulated t-helper lymphocytes in patients with common variable immunodeficiency

Common variable immunodeficiency [CVID] is the most common symptomatic primary antibody deficiency, characterized by reduced serum immunoglobulins levels and increased susceptibility to recurrent pyogenic infections. In this study, we evaluated CD40 ligand expression on stimulated versus unstimulated T-helper lymphocytes of nine Common variable immunodeficient patients in comparison with fifteen normal controls. Phorbol myristate acetate [PMA] and Ionomycin were used to stimulate cells in vitro. After six hours stimulation, the cells were subjected to surface staining with three-color staining procedure. Events were analyzed by flow cytometer, using FloMax software. Results were reported as the percentage of lymphocytes expressing CD markers. We did not find any significant statistical difference in CD40 ligand expression between patients and controls [p>0.05], despite having stimulation documented by CD69 expression as activation marker in each run. The results of this study are in agreement with some other studies, indicating that CD40 ligand expression on stimulated T-helper lymphocytes of Common variable immunodeficiency patients is similar to normal controls