Comparing the effect of Toll-like receptor agonist adjuvants on the efficiency of a DNA vaccine

We have investigated whether poly(I:C) Toll-like receptor 3 (TLR3) and resiquimod Toll-like receptor 7 (TLR7) agonists can serve as vaccine adjuvants and promote the efficiency of therapeutic DNA vaccination against tumors expressing the human papilloma virus 16 (HPV-16) E7 protein. For this purpose, C57BL/6 mice were inoculated with 2 × 10⁵ TC-1 cells, and they were then immunized with HPV-16 E7 DNA vaccine alone or with 50 μg of resiquimod or poly(I:C) individually. We found that poly(I:C) and resiquimod could induce more antigen-specific lymphocyte proliferation and cytolytic activity compared to vaccination with E7 DNA alone. While E7 DNA had no significant inhibitory effect on tumor growth, co-administration of poly(I:C) and resiquimod with E7 DNA induced significant tumor regression. Peripheral and local cytokine assays demonstrated that co-administration of poly(I:C) and resiquimod with E7 DNA induced circulating antigen-specific IFN-γ and nonspecific intratumoral IL-12. TLR3 and TLR7 agonists can be used to enhance the immune response to DNA vaccine immunogens. Taken together, these data indicate that combined vaccination with DNA encoding HPV-16 E7 plus TLR agonists provides a strategy for improving the efficacy of a vaccine as a possible immunotherapeutic strategy for cervical cancer.     

Epigallocatechin‐3‐gallate enhances differentiation of acute promyelocytic leukemia cells via inhibition of PML‐RARα and HDAC1

The use of all‐trans retinoic acid (ATRA) has dramatically improved the treatment and survival rate of patients with acute promyelocytic leukemia (APL). However, toxicity and resistance to this drug are major problems in the treatment of APL with ATRA. Earlier studies have suggested that the green tea polyphenol epigallocatechin gallate (EGCG) induces cell death in hematopoietic neoplasms without adversely affecting normal cells. In the present study, the potential therapeutic effect of EGCG in APL and the underlying molecular mechanisms were investigated. EGCG (100 μM) significantly inhibited proliferation and induced apoptosis in HL‐60 and NB4 cells. This effect was associated with decreased expressions of multidrug resistance proteins ABCB1, and ABCC1, whereas the expressions of pro‐apoptotic genes CASP3, CASP8, p21, and Bax/Bcl‐2 ratio were significantly increased. EGCG, at 25 μM concentration, induced differentiation of leukemic cells towards granulocytic pattern in a similar manner to that observed for ATRA (1 μM). Furthermore, EGCG suppressed the expression of clinical marker PML/RARα in NB4 cells and reduced the expression of HDAC1 in leukemic cells. In conclusion, the results suggested that EGCG can be considered as a potential treatment for APL.     

Group A Streptococcal Serotypes Isolated from Healthy Schoolchildren In Iran

Serotypes of group A streptococci are still a major cause of pharyngitis and some post-infectious sequelae such as rheumatic fever. As part of the worldwide effort to clarify the epidemiological pattern of group A streptococci in different countries, the present study was conducted to assess the prevalence of Streptococcus pyogenes serotypes in Iran. A total of 1588 throat swabs were taken from healthy school children in the city of Gorgan during February and March 1999. Of those isolates, 175 resulted positive for group A streptococci. The distribution pattern was similar for girls and boys, with 10.8% and 11.2%, respectively. Urban school children showed a higher rate of colonization compared to those in rural areas. Serotyping was performed on 65 of the positive isolates using standard techniques, and only 21 (32%) were M-type isolates. Their profiles fell into four types with M1 predominating, which could reflect the presence of rheumatic fever in the region. However, when isolates were challenged for T-antigen types, nearly all were positive (94%). The pattern of T types was diverse (18 types), with the most common T types being T1 (26%), TB3264 (15%), TB\1-19 & B\25\1-19 (9.2%) and T2 & 2\28 (7.7%). When isolates were tested for opacity factor, only 23 (35%) were positive while 34 (52%) responded to the serum opacity reaction test. Although the number of isolates in this study was not sufficient to make any epidemiological conclusions, the scarcity of serotyping studies in Iran could render these data useful for future attempts to develop a streptococcal vaccine.     

Cytotoxic T lymphocytes and CD4 epitope mutations in the pre-core/core region of hepatitis B virus in chronic hepatitis B carriers in Northeast Iran

Backgrounds

Hepatitis B virus (HBV) is vulnerable to many various mutations. Those within epitopes recognized by sensitized T cells may influence the re-emergence of the virus. This study was designed to investigate the mutation in immune epitope regions of HBV pre-core/core among chronic HBV patients of Golestan province, Northeast Iran.

Methods

In 120 chronic HBV carriers, HBV DNA was extracted from blood plasma samples and PCR was done using specific primers. Direct sequencing and alignment of the pre-core/core region were applied using reference sequence from Gene Bank database (Accession Number AB033559).

Results

The study showed 27 inferred amino acid substitutions, 9 of which (33.3%) were in CD4 and 2 (7.4%) in cytotoxic T lymphocytes’ (CTL) epitopes and 16 other mutations (59.2%) were observed in other regions.

Conclusions

CTL escape mutations were not commonly observed in pre-core/core sequences of chronic HBV carriers in the locale of study. It can be concluded that most of the inferred amino acid substitutions occur in different immune epitopes other than CTL and CD4.

     

Interleukin 10 gene promoter polymorphisms (rs1800896, rs1800871 and rs1800872) and haplotypes are associated with the activity of systemic lupus erythematosus and IL10 levels in an Iranian population

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with unknown aetiology. According to the role of interleukin 10 (IL10) in SLE pathogenesis, the genetic alterations in its promoter region could be associated with elevated IL10 levels and exacerbated disease. Here, we investigated the association of genotype and haplotype frequencies of three IL10 gene promoter polymorphisms with susceptibility to SLE, IL10 plasma levels and disease activity of patients in an Iranian population. A total of 116 SLE patients and 131 healthy subjects were enrolled. The PCR‐RFLP technique was used to detect IL10 promoter genotypes at the positions of ?1082 (G/A), ?819 (C/T) and ?592 (C/A) in association with IL10 plasma levels and SLEDAI scores. The GG genotype of ?1082 polymorphism was associated with the increased risk of SLE [OR = 2.65, 95% CI (1.21–5.82), p‐value = 0.046]. The CC genotype in ?819 region was associated with SLE susceptibility [OR = 3.38, 95% CI (1.26–9.07), p‐value = 0.034] and C allele was introduced as risk allele [OR = 1.86, 95% CI (1.15–3.01), p‐value = 0.009] in this region. IL10 plasma levels were overexpressed in CC genotype carriers of ?592 SNP and decreased in AA genotype carriers of ?1082. IL10 was also increased in SLE patients with CGT (?592/?1082/?819) haplotype. The SLEDAI score was higher among CC genotype carriers at the position of ?592 and TT genotype carriers at the region of ?819. SLEDAI was also elevated among patients with CGC (?592/?1082/?819) and CAC (p = 0.011) haplotypes. The present study suggests that the IL10 –819(C/T), ?1082(G/A) and ?592(C/A) polymorphisms and the haplotypes are associated with SLE susceptibility, increased disease activity and elevated IL10 levels. While this is the first time to report such an association in an Iranian population, further studies are needed to confirm these findings.