Genetic Diversity of HPV 16 and HPV 18 Based on Partial Long Control Region in Iranian Women.

BACKGROUND: Human papillomavirus (HPV) 16 and HPV 18 account for 75% of all cervical cancers. The L1 gene, encoding the major surface protein (MSP), is used to classify HPV types (lineages and sublineages), genotypes, and intratypic variants. Therefore, this study aimed to investigate the lineages, sublineages, genetic variabilities, and mutation effects on transcription factor binding sites by using partial sequences of the HPV 16 and HPV 18 long control regions (LCRs) in these samples. MATERIALS AND METHODS: After DNA isolation from 56 positive samples, the LCR of HPV 16 and HPV 18 were amplified using specific primers, and phylogenetic trees were drawn through MEGA X. Compared to the reference sequences, single nucleotide polymorphisms (SNPs) were identified. The transcription binding sites were also evaluated using the online PROMO database. RESULTS: The LCRs of 52 samples were successfully sequenced. Overall, 81.58% of all HPV 16 variants belonged to the D1 sublineage, followed by A4 (13.16%), A1 (2.63%), and C1 (2.63%) sublineages. All HPV 18 isolates belonged to A sublineage, 92.85% to A3 sublineage, and 7.15% to A4 sublineage. Out of 27 SNPs in the HPV 16 LCR, A7382T, T7384G, C7387T, C7393G, A7431G, T7448C, and C7783A were HPV 16-specific. Also, among 14 SNPs in the HPV 18 LCR, C7577A and A7943T were not previously reported. An insertion (C) between 7432 and 7433 positions was identified in all studied HPV 16 variants. Besides, most of the HPV 16 mutations were embedded in the YY1, TFIID, Oct-2, and NF-1 binding sites, while c-Fos and MBF1, as the most common binding sites, were affected by HPV 18 LCR mutations. CONCLUSION: The present results showed that D1 and A3 were the dominant sublineages of HPV 16 and HPV 18, respectively. Therefore, women infected with these variants need to be examined in further longitudinal studies to obtain more information about the oncogenic potential of these dominant variants in Iran. Besides, YY1, TFIID, Oct-2, NF-1, c-Fos, and MBF1 were the most frequent binding sites, which were influenced by the mutations.

Evaluation of the thermal stability of live-attenuated Rubella vaccine (Takahashi strain) formulated and lyophilized in different stabilizers.

Live attenuated viral vaccines are difficult to handle and often sensitive to temperature. The viral titer may drop during the processing and storing stage, especially at high temperatures. Using live attenuated viral vaccines successfully depends on keeping the sufficient potency required for an immune response. Although freeze-drying makes the vaccine more stable, in the absence of appropriate stabilizer the process may affect the structure and viability of the viruses. Therefore, the formulation of vaccine by means of an appropriate stabilizer plays a crucial role in the stability of viral structure and potency of the vaccine. This study aimed to evaluate the effect of two new stabilizers, including a Trehalose-based stabilizer (T) and a stabilizer containing sucrose, human serum albumin and sorbitol (S) on the thermal stability of lyophilized live-attenuated Rubella virus (Takahashi strain). Two Rubella vaccines were formulated using different stabilizers and were lyophilized. The potency of produced vaccines was investigated using accelerated stability test. To determine the pattern of thermal stability of reconstituted vaccines in 24 h, incubating at three different temperatures and continuous sampling was also included in this study. The viral titer was calculated by TCID50 method. The regression analysis revealed that T vaccine found the sufficient stability compared to commercial Rubella vaccine containing a gelatin-based (G) stabilizer.

The Effect of Various Stabilizers on Preserving Immunogenicity of Lyophilized Mumps Vaccines.

BACKGROUND: Chemical stabilizers are added to live attenuated vaccines for enhancing the virus stability. The aim of this study was to evaluate the effect of various stabilizers on preserving immunogenicity of lyophilized mumps vaccines. STUDY DESIGN: An experimental study. METHODS: Three mumps vaccines with different formulations were inoculated to three groups of Guinea pigs. Sterile water was injected to eight Guinea pigs as a control group. Blood samples were collected before inoculation and on 14, 28 and 42 d after vaccine injection. Mumps antibodies in the sera were measured using hemagglutination inhibition assay (HAI). RESULTS: All three formulated mumps vaccines induced antibody in Guinea pigs after two weeks. Formulation 1 containing trehalose dihydrate and formulation 2 comprised human serum albumin stimulated antibodies in the higher level than Razi routine formulation. CONCLUSIONS: Various stabilizers have different preservation potencies that differently affect immune response against virus. More stable and more immunogenic vaccines can be produced using stabilizers containing trehalose dihydrate.

Anti-rubella, Mumps and Measles IgG Antibodies in Medical Students of Tehran University.

Measles, mumps and rubella are viral infectious diseases that may result in serious complications. Since the production of vaccines, the number of cases of these diseases has been dropped. Nevertheless, these infectious diseases are still one of the major health problems in developing countries. In this study, in order to evaluate the protective responses against measles, mumps and rubella, the level and avidity of virus-specific IgG antibodies were measured in 53 medical students of Tehran University, aged between 20-30 years. Except for mumps vaccine, all the students had been vaccinated against measles and rubella according to Iran's nationwide mass vaccination protocol for all persons aged 5-25 in 2003. Our results showed that 96.2% of the volunteers had a protective level (>15 IU/ml) of IgG against rubella, 79.2% had a protective level (>11 IU/ml) of IgG against measles and 64.16% had a protective level (>11 IU/ml) of IgG against mumps. Over ten years after nationwide measles-rubella vaccination campaign, most young adults aged 20-30 had protective levels of humoral immunity against measles and rubella. However, Iranian young population is still unvaccinated against mumps, and therefore relatively large number of young adults had no protective level of IgG against it. This finding may be due to reduction in circulating of wild strain. We recommend screening of medical students for immunity against infectious agents such as measles, mumps, rubella, because they are at a high risk of these infectious agents.

Evaluation of the thermal stability of a novel strain of live-attenuated mumps vaccine (RS-12 strain) lyophilized in different stabilizers.

The stability of live-attenuated viral vaccines is important for immunization efficacy. Here, the thermostabilities of lyophilized live-attenuated mumps vaccine formulations in two different stabilizers, a trehalose dihydrate-based stabilizer and a stabilizer containing sucrose, human serum albumin and sorbitol were investigated using accelerated stability tests at 4°C, 25°C and 37°C at time points between 4h (every 4h for the first 24h) and 1 week. Even under the harshest storage conditions of 37°C for 1 week, the 50% cell culture infective dose (CCID50) determined from titrations in Vero cells dropped by less than 10-fold using each stabilizer formulation and thus complied with the World Health Organization's requirements for the potency of live-attenuated mumps vaccines. However, as the half-life of the RS-12 strain mumps virus infectivity was lengthened substantially at elevated temperatures using the trehalose dihydrate (TD)-based stabilizer, this stabilizer is recommended for vaccine use.