Abstract P4-11-04: Targeted vaccination against human a-lactalbumin may provide immunotherapy and immunoprevention of triple negative breast cancer

We have previously shown that a-lactalbumin vaccination mediates protection against the development of murine breast cancer in the absence of any detectable inflammatory changes in all normal non-lactating tissues examined. Based on these results, we have proposed that α-lactalbumin vaccination of healthy, cancer-free, adult women may provide safe and effective immunoprevention of breast cancer. Several issues have been raised over the past several years questioning the feasibility of applying this autoimmune strategy for breast cancer immunoprevention in the normal, healthy, cancer-free adult female population. These concerns have focused on whether adult women would be immunologically responsive to human α-lactalbumin, whether a history of lactation would create an insurmountable tolerance that would preclude generating effective immunity against α-lactalbumin, whether α-lactalbumin is immunologically available in human breast tumors, and whether expression of α-lactalbumin in normal non-breast tissues would predispose to systemic autoimmune complications. Here we provide an accumulation of several new findings that directly address these issues: 1) In vitro priming of peripheral blood mononuclear cells (PBMC) from normal healthy adult women results in frequencies of α-lactalbumin-specific interferon-gamma (IFNγ) producing T cells that are consistent with those mediating protection against breast tumor formation in mice; 2) Frequencies of IFNγ-producing T cells and the level of protection from the development of breast tumors are virtually identical whether vaccination occurs in parous mice with a history of lactation and breastfeeding or whether vaccination occurs in non-parous mice with no history of lactation; 3) ONCOMINE data base searches repeatedly show highly significant overexpression of α-lactalbumin in triple negative breast cancer (TNBC). This expression was confirmed experimentally using several methods including RT-PCR, Western blot analysis, and longitudinal visualization of α-lactalbumin gene expression during in vivo growth of human TNBC in immunodeficient mice. This in vivo visualization of α-lactalbumin gene expression was facilitated by measuring bioluminescence from growing human HCC1937 TNBC cells stably transfected with a lentivirus designed to regulate firefly luciferase expression under control of the human α-lactalbumin promoter; and 4) Evidence from the Human Protein Atlas indicates negative immunohistochemical staining for α-lactalbumin in 78 normal human tissues examined, thereby confirming the widely held view that α-lactalbumin expression in normal human tissues is confined exclusively to the lactating breast. Collectively, these findings indicate that normal, healthy, adult women are capable of mounting an immune response to human α-lactalbumin, that a history of lactation and breastfeeding has no impact on the induced immunity and the protection it provides against the development of breast cancer, and that α-lactalbumin vaccination may be most effective in providing therapy and immmunoprevention of TNBC, the most aggressive form of breast cancer and the most common variant occurring in women with BRCA1 mutations (supported by NIH R01 CA140350).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-11-04.

Molecular diversity of the HLA-A*19 group of alleles in North Indians: possible oriental influence

The present study aims to determine the genetic diversity of the HLA-A19 allelic family in the North Indian and Japanese populations. The HLA-A*19 group of alleles occurred at similar frequencies in North Indians and Japanese as in Caucasians. All the known serological splits of HLA-A19 were observed among the North Indians, i.e. A*33 (15.6%), A*32 (8.6%), A*31 (3.5%), A*30 (3%), A*29 (1.2%) and A*74 (0.77%), while only A*30 (0.7%), A*31 (17.6%) and A*33 (11.7%) were observed in the Japanese. High resolution analysis indicated that the A*29, A*30, A*31 and A*32 alleles were represented by only single subtypes among the North Indians while the HLA-A*33 group comprised two alleles, A*3301 (4.3%) and A*3303 (43.7%). All 15 of the HLA-A*33 positive samples from the Tamil population of South India were found to be A*3303. One novel subtype of A*33, A*3306 was also observed in the North Indian sample. Conversely, only one subtype each of A*30, A*31 and A*33 was encountered in the Japanese population, of which A*3101 and A*3303 were the most frequent (58.5% and 39%, respectively, among the HLA-A*19 group of alleles). All other subtypes of A19 were not found in the Japanese in the present study. The study suggests a significant amount of genetic admixture in the North Indian gene pool from other racial groups, with profound oriental influence.

HLA-A*3306, a novel variant in the Indian population

We describe a new HLA-A allele, A*3306, which was identified by sequencing based typing (SBT) in an individual of Indian origin. A*3306 is similar to A*3303, with a difference at position 228 (A to G). This difference leads to an amino-acid change at codon 52 from Ile (ATA) to Met (ATG). Until now this position has been considered conserved.

Genetic Diversity in the Human Major Histocompatibility Complex: Lessons for Vaccination Approaches to HIV Infection

The major histocompatibility complex (MHC) harbours genes that have a primary function of regulating immune responsiveness. Our data on the distribution patterns of molecular subtypes of HLA class I and II extended haplotypes in India suggest that: (1) Asian Indians have extreme diversity in the MHC region, with several novel and unique alleles and disease-associated MHC haplotypes (e.g. the autoimmune-favouring A26-B8-DR3 haplotype); (2) there have been selective environmental and microbial pressures in India that directed either the generation of novel alleles through founder effect or the expansion of other alleles due to geophysical or socio-economic barriers, and (3) Asian Indians have a unique repertoire of peptide-presenting molecules to deal with pathogen-derived autoreactive antigens. This level of polymorphism concentrated within the MHC presents a formidable obstacle to the development of peptide-based vaccines, e.g. for AIDS. Further, studies conducted by us and others have provided a genetic basis for the possible predisposition and fast progression of HIV infections in the Indian population. Since there is selective predominance of different HLA alleles and haplotypes in different populations, a dedicated global screening effort is required to develop MHC-based vaccines against infectious diseases.

Immunogenetics of peripheral arteriopathies

Takayasu's arteritis (TA) and thrombangiitis obliterans (Buerger's disease) are idiopathic, inflammatory arteriopathies with strong indications for the involvement of autoimmunity and host genetic factors in their immunopathogenesis. The exact etiology of these arteriopathies still remains unknown even after almost nine decades of their description. A series of immunogenetic studies conducted worldwide seeking to define genetic factors in governing immune response in these diseases have yielded conflicting results on the involvement of HLA molecules. While an association of HLA-B5 or its molecular subtypes with Takayasu's arteriitis has been emphasized in patients from Japan, Korea and India, no such association has been reported in Mexican and North American patients. On the other hand, a limited data is available on the association of HLA antigens with Buerger's disease. In this article, we provide an overview of the immunogenetics of Buerger's disease and Takayasu's arteriitis in the context of studies in North Indian patients and those in other ethnic groups. Our studies indicate a positive association of Takayasu's arteriitis with the HLA-B5 molecule with no preferential association with its two major subtypes. In Buerger's disease, we have observed a strong positive association with HLA-DRB1*1501 consistent with the findings in Japanese patients. These results suggest an important role of HLA linked factors in governing susceptibility to both arteriopathies.

Molecular diversity of HLA-A*02 in Asian Indians: predominance of A*0211

The North Indians are considered predominantly Caucasoid with an admixture of genes from the Mongoloid and Aryan races. The present study was undertaken to investigate the genetic diversity of HLA-A*02 in the North Indian population and determine the frequency distribution of its molecular subtypes at the population level. The study revealed a high occurrence of A*0211 (33.8%) in this population along with increased frequencies of the common Oriental alleles, A*0206 (7.5%) and A*0207 (32.5%) and also of HLA-A*0205 (15%) commonly observed in negroid populations. HLA-A*0211 has only been reported with very low frequencies among the Ticuna Jews, Thai population, and Colombian Blacks in the malaria endemic areas of Africa. Significantly, we observed an unexpectedly low frequency of A*0201 (3.8%) in contrast to its distribution in Western Caucasians in whom it constitutes 95% of the HLA-A2 repertoire. Prevalence of HLA-A*0211 at very high frequencies among North Indians may be a consequence of the founder effect, racial admixture or selection pressure due to environmental factors in this population.

Immunogenetic analysis of Buerger's disease in India

In order to understand the role of HLA linked factors in determining susceptibility to Buerger's disease, we have studied 21 unrelated Asian Indian patients belonging to the North Indian states of Punjab, Haryana, Uttar Pradesh and Delhi, representing mainly a lower socioeconomic background. The data was compared with healthy controls belonging to the same ethnic group. The study revealed an over representation of HLA-B40 (60+61) (chi2=6.12; P<0.02) and DR2 (chi2=10.2; P<0.002). Amongst the patients no particular association or linkage disequilibrium with any of the five alleles of the MIC-A gene could be derived in the small sample size studied.

Immunogenetic analysis of Takayasu arteritis in Indian patients

The distribution of HLA-A, B, C and DR antigens was determined in a cohort of 104 unrelated Indian patients with Takayasu arteritis (TA) belonging to the North Indian states of Punjab, Haryana, Uttar Pradesh and Delhi. The data was compared with healthy controls belonging to the same ethnic group. In addition, polymorphism in the MHC class I chain related A (MIC A) gene was studied in a group of 25 TA patients and 40 healthy controls. The data revealed a strong association of the disease with HLA-B5 (chi2=22.5, P<1 x 10(-6), RR=3.08) as well as its two common serological subtypes, B51 (chi2=20.5) and B52 (chi2=18.5). No particular association was observed with any of the five alleles of the MIC A gene, nor any linkage disequilibrium could be established with these alleles and those of HLA-B locus in this population. The observation suggest that HLA linked genes are definitely involved in the development of Takayasu arteritis and that the disease in Indian subjects is associated with HLA-B5 and its two serological subtypes, B51 as well as B52.