Novel adjuvants & delivery vehicles for vaccines development: a road ahead.

The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines.

Intronic SNPs of TP53 gene in chronic myeloid leukemia: Impact on drug response.

BACKGROUND: TP53, located on chromosome 17p13, is one of the most mutated genes affecting many types of human cancers. Thus, we aimed at investigating the association of SNPs in TP53 gene with chronic myeloid leukemia (CML). MATERIALS AND METHODS: A total of 236 CML and 157 control samples were analysed for mutations in TP53 gene using polymerase chain reaction followed by direct sequencing. RESULTS: Sequencing analysis for mutations in exons 7-9 of the TP53 gene revealed four SNPs, three in intron 7 (C14181T, T14201G, and C14310T) and one SNP in intron 6 (A13463G) of TP53 gene. The mutation C14181T is located at position 72 base pairs downstream of the 3'-end of exon 7 of the P53 gene. This mutation is in complete linkage disequilibrium with a T14201G mutation, 20 base pairs further downstream occurring at position 14201. This mutation occurred only in the presence of C14181T mutation and these mutations showed association with advanced phase and cytogenetic poor response. Another two novel mutations, C14310T in intron 7 and A13463G in intron 6 were also found to be associated with cytogenetic poor response. CONCLUSION: Our study suggests that TP53 intronic SNPs might have a strong influence on disease progression and poor response in CML patients.

Association of CYP3A5*3 polymorphism with development of acute leukemia.

BACKGROUND: CYP3A5 was observed to be an important genetic contributor to inter individual differences in CYP3A-dependent drug metabolism in acute leukemic patients. Loss of CYP3A5 expression was mainly conferred by a single nucleotide polymorphism at 6986A>G (CYP3A5*3). We investigated the association between CYP3A5*3 polymorphism and acute leukemia. MATERIALS AND METHODS: Two hundred and eighty nine acute leukemia cases comprising of 145 acute lymphocytic leukemia (ALL), 144 acute myeloid leukemia and 241 control samples were analyzed for CYP3A5*3 polymorphism using PCR-RFLP method. Statistical analysis was performed with SPSS version (15.0) to detect the association between CYP3A5*3 polymorphism and acute leukemia. RESULTS: The CYP3A5*3 polymorphism 3/3 genotype was significantly associated with acute leukemia development (χ(2)- 133.53; df-2, P 0.000). When the data was analyzed with respect to clinical variables, mean WBC, blast % and LDH levels were increased in both ALL and AML cases with 3/3 genotype. The epidemiological variables did not contribute to the genotype risk to develop either AML or ALL. CONCLUSION: The results suggest that the CYP3A5*3 polymorphism might confer the risk to develop ALL or AML emphasizing the significance of effective phase I detoxification in carcinogenesis. Association of the polymorphism with clinical variables indicate that the 3/3 genotype might also contribute to poorer survival of the patients.

Codon 72 and G13964C intron 6 polymorphisms of TP53 in relation to development and progression of breast cancer in India.

The p53 protein is at the center of cell regulatory pathways influencing transcription and activity of several replication and transcription factors. In exon 4 of the gene TP53, a codon 72 polymorphism causing an Arg/Pro substitution has been reported in breast and other cancers. This substitution is in the putative SH3 binding domain of p53 protein, influencing binding capacity and thereby functional properties. In the present investigation of a relatively large series of cases in India, the frequency of the homozygous arginine genotype (33.2%) was significantly higher in the breast cancer group as compared to controls (19.6%), χ2 =11.791 (P=0.003). Patients with premenopausal breast cancer had a more elevated frequency (41.1%) than postmenopausal cases (25.4%) although the genotype frequency distribution did not show significant variation with respect to hormonal receptor status. Elevation was greatest in patients in advanced stages of cancer. The hetrozygote frequency (Arg/Pro) was also found to be increased in overweight and obese women with breast cancer. TP53 codon 72 polymorphism might predispose individual for the development of breast cancer as well as to bad prognosis. Intronic variants may affect gene regulation through aberrant splicing or through disruption of critical DNA-protein interaction. While no significant association was observed with relation to CC genotype as well as C allele of G13964C intron polymorphism with breast cancer, the C allele frequency showed association with respect to other risk confounding factors which might play role in progression of breast cancer.

Association of an MDR1 gene (C3435T) polymorphism with acute leukemia in India.

The multidrug resistance (MDR1) gene product P-glycoprotein is a membrane bound protein that functions as an ATP-dependent efflux pump, transporting exogenous and endogenous substrates from the cells. Since it plays an important role in chemotherapy, there is an increasing interest in the possible significance of genetic variation in MDR1. Our main objective was to study the MDR1gene polymorphism at C3435T with reference to development and progression of acute leukemia. The present study included 290 acute leukemia cases, comprising of 147 acute lymphocytic leukemia (ALL), 143 acute myeloid leukemia and 249 age-sex matched control samples for the analysis of MDR1 C3435T polymorphism, by the PCR-RFLP method. The MDR1 genotype distribution revealed an elevated frequency of the TT genotype in ALL cases (51.7%) as compared to controls (28.9%), whereas AML group did not show any association. The mean white blood cell count, blast% and LDH levels were increased in ALL patients with the CC genotype. No deviation was observed with respect to hematoglobin, platelet count and disease free survival in ALL patients. The association of CC genotype with clinical variables in ALL indicated that the CC genotype with high expression might be eliminating antileukemic drugs (anthracyclines, Daunorubicin, Vincristeine, Mitoxanthrone) which are P-gp substrates, leading to lower intra cellular drug concentrations and a poor prognosis. Such an association with the CC genotype was not observed in AML. In conclusion, these results suggested that the MDR1 TT genotype might influence risk of development of acute lympoblastic leukemia and the CC genotype might be linked to a poor prognosis of ALL.

Analysis of CYP3A5*3 and CYP3A5*6 gene polymorphisms in Indian chronic myeloid leukemia patients.

CYP3A5 is a member of the CYP3A gene family which metabolizes 50% of therapeutic drugs and steroid hormones. CYP3A5*3 and CYP3A5*6 polymorphisms exhibit inter-individual differences in CYP3A5 expression. The CYP3A5*3 allele (A6986G transition in intron 3) results in loss of CYP3A5 expression and the CYP3A5*6 allele (G14690A transition in exon 2, leading to the skipping of exon 7) is associated with lower CYP3A5 catalytic activity. The aim of the present study was to investigate their influence on susceptibility to chronic myeloid leukemia (CML). 265 CML cases and 241 age and sex matched healthy controls were analyzed by the PCR-RFLP technique. The frequencies of homozygous 3/3 genotype and CYP3A5*3 allele were elevated significantly in the CML group compared to controls (χ²=93.15, df=2, p=0.0001). With respect to clinical parameters, CYP3A5*3 allele frequency was increased in patients with advanced phase of the disease (0.71) as compared to those in chronic phase (0.65). Patients without hematological response (minor/poor) had higher frequency of 3/3 genotype (54.54%) as compared to those with major hematological response (41.2%). CYP3A5*6 allele was not observed in cases as well as in controls. Our study suggests that the CYP3A5*3 gene polymorphism is significantly associated with the risk of CML development and disease progression.

Association of the GSTP1 gene (Ile105Val) polymorphism with chronic myeloid leukemia.

The GSTP1 enzyme plays a key role in biotransformation and bioactivation of certain environmental pollutants such as benzo[a]pyrene-7, 8-diol-9,10-epoxide (BPDE) and other diol epoxides of polycyclic aromatic hydrocarbons. It catalyses the detoxification of base propanols that arise from DNA oxidation thus offering cellular protection against oxidative stress. A single nucleotide polymorphism at codon 105 results in the substitution of isoleucine (Ile) to valine (Val) causing a metabolically less active variant of the enzyme. We here assessed the impact of the GSTP1 codon 105 polymorphism in chronic myeloid leukemia (CML) development and therapy response. The Ile105Val polymorphism was analyzed using a PCR-RFLP technique. Two hundred and sixty patients with CML and 248 healthy, age and sex matched controls were included in the study of associations with patient characteristics and treatment outcome. The GSTP1 Ile105Val polymorphism was significantly associated with CML development (?2 = 9.57; df = 2; p = 0.0084). With respect to clinical phase, CML patients in advanced phase (accelerated and blast crisis) had higher frequency of heterozygous (Ile/Val) genotype (47.62%) compared to chronic phase (36.5%). Further 54.5% of patients in blast crisis carried valine allele as compared to those in chronic phase (36.5%). The frequency of combined genotypes (Ile/Val, Val/Val) was elevated in cytogenetic poor (41.6%) and minor (53.57%) responders as compared to major (38.51%) responders. Hence the present study suggests that GSTP1 Ile105Val polymorphism with reduced GSTP1 enzyme activity might influence CML development, progression and response rates.

Association of a CYP17 gene polymorphism with development of breast cancer in India.

The human CYP17 gene, located on chromosome 10q24.3, plays a key role in sex steroid synthesis, mainly related to estrogen. A 5' UTR polymorphism involving a single base pair change in the promoter region results in increased transcriptional activity. In the present study of 250 breast cancer cases and 250 ma tched controls, the A1 genotype frequency was elevated in the disease group, while the A2 genotype frequency demonstrated no association. When data were stratified by risk conferring group, however, the A2 genotype frequency was increased in postmenopausal breast cancer cases (4.2%), patients positive for a family history of breast cancer (5.5%), high BMI, estrogen receptor (6.2%) and progesterone receptor negative (5.0%) status, HER2/neu positive (7.7%) status, positive node status (5.0%) as well as advanced stage of the disease. The A1A1 genotype linked with increased production of androgens might impact on onset of breast cancer while the A2 allele showed associations with respect to important risk conferring parameters.

Association of CYP1A1*2 polymorphisms with breast cancer risk: a case control study.

BACKGROUND: The Cytochrome P-4501A1 (CYP1A1) gene, located on chromosome 15q, is involved in the metabolism of carcinogens mainly polycyclic aromatic hydrocarbons as well as estrogen. It is considered as candidate gene for low-penetrance breast cancer susceptibility. Hence the present study aims to discuss the role of CYP1A1 polymorphisms in breast cancer. MATERIALS AND METHODS: A total of 250 breast cancer patients and the same number of healthy age-matched controls were analyzed for the polymorphism of CYP1A1*2 by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: In the present study, association of CYP1A1*2 (Ile 462Val) polymorphism with breast cancer was studied. Only one breast cancer patient was observed to be homozygous for Val allele but none among controls. The frequency of heterozygous Ile/Val genotype was found to be increased significantly in breast cancer patients (68.1%) as compared to controls (51.0%). Higher frequency of heterozygotes for Val allele was observed among premenopausal breast cancer patients and patients with high BMI, positive for HER2/neu status and advanced stage of the disease in comparison to the corresponding groups. No significant association of CYP1A1*2 polymorphism was observed with occupation, estrogen receptor and progesterone receptor status of breast cancer patients. CONCLUSIONS: In conclusion, our results suggest a significant correlation between CYP1A1*2 expression and the occurrence of breast cancer.

Molecular mechanisms in response to phosphate starvation in rice.

Phosphorus is one of the most important elements that significantly affect plant growth and metabolism. Among the macro-nutrients, phosphorus is the least available to the plants as major phosphorus content of the fertiliser is sorbed by soil particles. An increased knowledge of the regulatory mechanisms controlling plant's phosphorus status is vital for improving phosphorus uptake and P-use efficiency and for reducing excessive input of fertilisers, while maintaining an acceptable yield. Phosphorus use efficiency has been studied using forward and reverse genetic analyses of mutants, quantitative genomic approaches and whole plant physiology but all these studies need to be integrated for a clearer understanding. We provide a critical overview on the molecular mechanisms and the components involved in the plant during phosphorus starvation. Then we summarize the information available on the genes and QTLs involved in phosphorus signalling and also the methods to estimate total phosphate in plant tissue. Also, an effort is made to build a comprehensive picture of phosphorus uptake, homeostasis, assimilation, remobilization, its deposition in the grain and its interaction with other micro- and macro-nutrients as well as phytohormones.

PvuII polymorphism of estrogen receptor-α gene in breast cancer.

BACKGROUND: Estrogen receptor (ER) is a ligand-inducible transcription factor that mediates estrogen action in target tissue. Several common polymorphisms of the ERα gene have been reported to be associated with alterations in receptor expression in breast cancer. MATERIALS AND METHODS: A case-control study was designed to compare 250 breast cancer patients with 250 age-matched healthy controls. The frequency distribution of PvuII polymorphism in the ERα gene was assessed by PCR-RFLP method. RESULTS: The frequency of the PP genotype (35.3%) was increased significantly in breast cancer patients when compared to controls (19.8%), with a corresponding increase in P allele frequency (χ(2)= 16.4; P = 0.0003). The OR for genotypes PP vs. Pp was 1.989 (95% CI: 1.2708 to 3.113). Premenopausal women with breast cancer had an elevated frequency of the PP genotype (22.8%) as compared to postmenopausal women (16.8%). The frequency of the PP genotype was increased in patients positive for ER and HER-2/neu as compared to those with receptor-negative status. The pp and p allele frequencies were increased in progesterone-receptor-negative status. When stage of the disease was considered, both Pp and pp genotype frequencies were elevated in patients with advanced stage breast cancer. The frequency of the P allele and PP genotype frequencies tended to increase with increase in body mass index, whereas the Pp genotype frequency was elevated only in obese patients. The reverse was observed in the case of pp genotype frequency. CONCLUSION: The study thus highlighted the influence of ERα PvuII polymorphism on the development and progression of breast cancer.

Enhanced mucosal and systemic immune response with intranasal immunization of mice with HIV peptides entrapped in PLG microparticles in combination with Ulex Europaeus-I lectin as M cell target.

The predominant route of HIV infection is through the sexual transmission via M cells. Most of the peptide and protein vaccines show poor transport across the epithelial barrier and are commonly administered by parenteral route. In the present study four HIV peptides from envelope (gp 41-LZ (leucine zipper), gp 41-FD (fusion domain) and gp120-C2) and regulatory (Nef) region in poly lactic-co-glycolide (PLG) micro-particle delivery were evaluated in mice of outbred and with different genetic background to compare immune response versus MHC restriction. Out of the combinational and single routes of immunization attempted, the single route maintained the IgG, IgA and sIgA in sera and washes for longer duration as compared to combinational routes in which the response was declined. The study demonstrated that single intranasal immunization offered significantly higher immune response (p<0.05) over oral and rectal mucosal routes in terms of inducing systemic as well as mucosal response. Also, the specific activity measurement of IgA and IgG in sera and sIgA in washes were correlating to the antibody titers. However, the intramuscular route of immunization generated systemic response only. The entrapment of plant lectin UEA-1 a ligand specific for M cells in micro-particle further enhanced the immune response in all the mucosal routes. The IgG isotypes generated were of IgG1 and IgG2a/2b in sera for all the peptides. The T cell proliferation response study with and without UEA-1 lectin in micro-particles showed significantly high (p<0.05) stimulation index (SI) with intranasal immunization for all the peptides from cells collected from spleen (SP), peyer's patches (PP) and lamina propria (LP) with SI in the order LP cells>PP>or=SP. The cytokine measurement profile of IL-2, IFN-gamma and IL-6 and low levels of IL-4 in the cultural supernatants of SP, PP and LP showed mixed CD4(+) Th1 and Th2 immune response. The p24 assay showed high percent inhibition of HIV-IIIB virus with sera and washes obtained from intranasal route. Thus, overall the study highlighted the combination of UEA-1 lectin with HIV peptides in micro-particles through intranasal immunization generated systemic as well as mucosal immune response.

Generating neutralizing antibodies, Th1 response and MHC non restricted immunogenicity of HIV-I env and gag peptides in liposomes and ISCOMs with in-built adjuvanticity.

For enhancing immunogenicity and develop vaccine strategies using peptide based constructs against HIV-1, a chimeric peptide containing V3 loop and transmembrane sequence of gp41 with two glycine motifs as spacer was constructed. The V3-gp41, gp41 peptide and p17 and p24 peptides separately or in a cocktail were entrapped with or without MA729 as an immunoadjuvant in liposomes or ISCOMs. The immunogenicity, antigen induced T-cell proliferation and cytokine profiles of various formulations were studied in four different inbred strains of mice of H-2d, H-2b, H-2k and H-2q haplotypes, keeping alum as a control adjuvant. Both liposomes and ISCOM preparations elicited high titer and long lasting antibody response (60 days and above). When compared to the alum formulation, the liposomes co-entrapped with MA729 produced high antibody levels, comparable with that induced by ISCOMs. Peptide in alum, liposomes and ISCOMs enhanced both antigen specific IgG2a and IgG2b isotypes and high T-cell stimulation index. Peptide formulations also induced antibodies with high affinity and in vitro neutralizated the formation of HIV-1 syncytia. T-cell supernatants contained high levels of IFN-gamma and IL-2. Thus formulation in these adjuvants induced a predominant Th1 like response with MA729 as a versatile novel delivery vehicle for stimulating the appropriate arm of the immune response that can selectively modulate MHC class I or MHC class II response. The above peptide can be of wide vaccination interest as a means to improve immune responses to several other HIV-1 antigens and may serve as candidates for vaccine development.