Background: Streptokinase is administered during acute myocardial infarction (AMI). It is prepared from beta haemolytic streptococci and in some cases pre-existing antibodies may compromise the use of streptokinase.Objective: To study levels of anti-streptokinase antibodies in AMI patients during thrombolytic therapy.Methods: Specific IgG, IgA, IgM and anti- streptokinase antibodies (ELISA) were studied in 246 cases. Pre-and post-therapy levels of these antibodies were examined in 10 cases given streptokinase for AMI.Findings: Neutralising anti-streptokinase was detectable in 61.7% of the controls which 0.43% of them had levels above the normal range. Neutralising anti-streptokinase antibodies showed a positive correlation with the level of IgG anti-streptokinase antibodies (r=+0.55, P<0.001).By streptokinase administration, antibody levels dropped in day 1; however, they rose to pre-therapy values afterwards. One patient with elevated antibodies to streptokinase had an adverse immunological reaction to streptokinase (serum sickness).Conclusion: Elevated pre-therapy levels of antibodies, the isotype IgG and possibly IgA, appear to be contradictory for further treatment with streptokinase.

Background: Immune deficiency in hemodialytic and uremic patients decreases antibody response after hepatitis B (HB) vaccination. Acceptable response among these patients is an antibody level above 100 mIU/ml. Objective: To determine antibody response in hemodialytic patients after hepatitis B vaccination. Methods: A cross sectional descriptive study with census sampling was implemented on hemodialytic patients in Bou-Ali Sina teaching hospital of Qazvin in 2000. Eliminating HBsAg positive and unvaccinated patients, final population was reduced from 70 to 63. Serum samples were tested by ELISA. Findings: Antibody level in 16 patients (25.4%) was undetectable and in overall 37 patients (58.7%) there was no protective antibody level (100 mIU/ml) despite vaccination. Response in female was 51.5% and in male was 30%. Conclusion: With regard to the risk of hepatitis B, completion of vaccination and quantitative test to determine the antibody response for hemodialytic patients is necessary.

Patients with inborn errors of immunity (IEI) are among the high-risk groups regarding COVID-19. Receiving booster doses (third and fourth) in addition to the standard doses is recommended in these patients. This study investigated the antibody response before and after a booster dose of Sinopharm vaccine in IEI patients.  Thirty patients (>12 years) with antibody deficiencies, referred to Imam Khomeini Hospital and Children's Medical Center in Tehran, were enrolled in this prospective cross-sectional study. All patients were fully vaccinated with the BBIBP-CorV vaccine (2 doses of Sinopharm). Initial measurements of anti-receptor-binding domain (anti-RBD) and anti-nucleocapsid (anti-N) IgG antibody responses were conducted by enzyme-linked immunosorbent assay (ELISA). Subsequently, all patients received a booster dose of the vaccine. Four to six weeks after booster injection, the levels of antibodies were re-evaluated.  Twenty patients with common variable immunodeficiency (CVID), 7 cases with agammaglobulinemia and 3 patients with hyper IgM syndrome were studied. Anti-RBD IgG and anti-N IgG antibodies increased in all patients after the booster. Our results indicated the need of receiving booster doses of the COVID-19 vaccine in patients with antibody deficiencies, even for enhancing humoral immune response specially in patients with CVID.

Background: Anthrax, as a zoonotic disease, is considered a major bioterror threat. Development of effective prophylactic approaches is needed to combat this disease. The protective antigen domain 4 (PAD4) has been extensively studied as a vaccine candidate against anthrax. Previously, we showed that PAD4 can be successfully encapsulated in poly (lactide-co-glycolide) (PLGA) -based particulate systems.Objectives: We aimed to determine if there is an intricate relationship between the parameters of PLGA particulate process and the associated immunogenicity.Methods: In this study, PLGA (50: 50) and PLGA (85: 15) with a similar molecular weight were used as the polymer variants. Polymer variants were evaluated using 3 adaptations of w/o/w solvent evaporation method. Six variants of PLGA-PAD4 particulate systems were developed and studied for size, antigen content, and immunogenicity.Results: NaCl in the external aqueous phase was required to achieve nonporous and spherical microparticles. Particle size was found to be dependent on the applied methods, and there was no significant difference in size by varying the PLGA compositions.PLGA variants showed a differential behavior with antigen encapsulation in the evaluated methods. The hydrophobic particulate vaccine with the mean diameter of ~3mmelicited the highest IgG titer, compared to particles with mean diameters of ~ 0.2 and ~7mm.Conclusions: This study could help determine the composition of novel PAD4-encapsulated PLGA-based vaccine formulations.

Introduction: Some viral infections have been suggested to trigger or cause autoimmune diseases. One of these viruses is parvovirus B19 which can have various rheumatologic manifestations. In this study we investigated the association between parvovirus and rheumatoid arthritis (RA), systemic lupus erythematosis (SLE), systemic sclerosis (SSc) and undifferentiated arthritis at the Rheumatological Clinic, Imam Khomeini hospital.Methods: In this sectional case-control study, IgM and IgG antibodies against parvovirus B19 were measured with ELISA in 41 patients with RA, 28 patients with SLE, 13 patients with SSc, 8 patients with undifferentiated arthritis as well as 90 healthy controls. The ELISA kit (DRG, Germany) was semiquantitative and qualititative.Results: Parvovirus B19 IgM was detected in one patient with RA, one with SSc and four in the control group. IgG anti- B19-specific antibody was detected in 58.5% of RA patients, 67.9% of SLE patients, 69.2% of SSc patients, 87.5% of undifferentiated arthritis patients as compared to 53.3% of controls. The results were compared between the patient and control groups (p>0.05).Conclusion: According to the results, there was no significant correlation for the antibody titer against parvovirus B19 in the patient and control group. The highly positive response of IgG against parvovirus in undifferentiated arthritis implies the need for more research.

Background: In addition to passive immunotherapy using anti-HER2 monoclonal antibodies, active immunotherapy via HER2 targeting is an interesting approach to inducing specific anti-tumor immune responses. We have recently reported the immunogenicity of HER2 subdomains following DNA immunization and HER2 protein boosting. In the present study, we evaluated the immunogenicity of different HER2 extracellular subdomains for the induction of anti-HER2 antibody response in BALB/c mice. Objective: To investigate and characterize antibody responses to human recombinant proteins of HER2 extracellular subdomains in immunized mice. Methods: Four subdomains of HER2 extracellular domain were expressed in E. coli; subsequently, purified recombinant proteins were intraperitoneally injected in BALB/c mice with Freund's adjuvant. The anti-HER2 antibody response was detected by ELISA, immunoblotting and flow cytometry. Results: All the four HER2 subdomains along with the full extracellular domain (fECD) were able to induce specific anti-HER2 antibodies. Although anti-HER2 subdomains antibodies could not react with eukaryotic recombinant fECD protein by ELISA, they were able to recognize this protein by immunoblotting under both reduced and non-reduced conditions. Furthermore, only the sera of mice immunized with fECD protein could recognize native HER2 on HER2 overexpressing tumor cells (>99%) by flow cytometry. Moreover, fECD immunized mice sera inhibited the proliferation of tumor cells by XTT assay. Conclusion: The prokaryotic recombinant proteins of HER2 extracellular subdomains are immunogenic, yet the induced specific antibodies do not react with the native HER2 protein due to the paucity of post-translation modifications and /or distortion of the native conformation of isolated HER2 extracellular subdomains which might be potentially effective for induction of cell mediated immune response against HER2.

Objective(s): Analysis of measles serum antibody responses is an important tool for evaluating the level of immunity in vaccinated people and for determining the factors which influence protective immunity. Usually antibody concentration values which are determined by quantitative assays are left censored, so standard analysis such as simple linear regression model may not be appropriate.Methods: Measles antibodies were measured using Enzyme Linked Immunosorbent Assay (ELISA) in 200 person aged 5-25 years before and after vaccination. A censored regression model proposed in order to reduce the effects of censored data in parameter estimating.Results: Twenty two persons (11 percent) of the sample had titer below detection limit which made censored data. 83 percent of children and teenagers (less than 16 years) and 88 percent of participant aged 16 and more were protective against measles disease, but there was no statistically significance between age and immunity (P=0.4).Conclusion: Although the number of females who had protective antibodies against measles was less than males, they possessed an average titer 42 percent higher than males (without considering covariates). This proportion changed into 39% by using the censored regression model and adjusting with respect to “antibody titer before vaccination”. Both ratios showed higher vaccine- induced protection in females (P<0.05).

Background and Objectives: In this study, the performance of three different commercial antibody assays for COVID-19 was examined and parameters affecting the antibody response were investigated. The correlation of patients’,chest CT results, procalcitonin, CRP, and D-dimer levels with the antibody response were retrospectively evaluated. Materials and Methods: COVID-19 antibodies were detected by three commercially available assays in each patient. Two of the assays were rapid immunochromatographic tests and-one was an ELISA-based IgG assay. SARS-CoV-2 RNA was tested by “, COVID-19 RT-qPCR Detection Kit”,using nasopharyngeal swab samples. The results of antibody tests were com-pared with each other, RT-qPCR, Biochemical parameters and chest CT findings. Results: RT-qPCR was positive in 46. 6% (41/88) of the evaluated patients among which 77. 3% (68/88) were healthcare workers. Seventeen (41. 4%) of viral RNA positive patients had a positive antibody result with at least two assays. Both of the rapid immunochromatographic tests had identical sensitivity of 36. 6% and specificity of 100%, compared to RT-qPCR assay,while the sensitivity of the ELISA based Euroimmune test was 43. 9%, and the specificity was 95. 7%. The sensitivity and specificity of the immunochromatographic tests were 75% and 100% respectively, compared to ELISA test result. There was a correlation between antibody positivity and old age and male gender. The presence of typical chest CT findings increased the antibody positivity 13. 62 times. Antibody positivity was also increased with the decrease in Ct value of the PCR assay. There was no significant relationship between the biochemical parameters (CRP, D-dimer and procalcitonin values) and the antibody or RT-qPCR results. Conclusion: There was a correlation between antibody response and male gender, older age, presence of symptoms, typical chest CT findings and low PCR-Ct value.