Clonal Structure of Rapid-Onset MDV-Driven CD4+ Lymphomas and Responding CD8+ T Cells

Abstract

Lymphoid oncogenesis is a life threatening complication associated with a number of persistent viral infections (e.g. EBV and HTLV-1 in humans). With many of these infections it is difficult to study their natural history and the dynamics of tumor formation. Marek's Disease Virus (MDV) is a prevalent α-herpesvirus of poultry, inducing CD4+ TCRαβ+ T cell tumors in susceptible hosts. The high penetrance and temporal predictability of tumor induction raises issues related to the clonal structure of these lymphomas. Similarly, the clonality of responding CD8 T cells that infiltrate the tumor sites is unknown. Using TCRβ repertoire analysis tools, we demonstrated that MDV driven CD4+ T cell tumors were dominated by one to three large clones within an oligoclonal framework of smaller clones of CD4+ T cells. Individual birds had multiple tumor sites, some the result of metastasis (i.e. shared dominant clones) and others derived from distinct clones of transformed cells. The smaller oligoclonal CD4+ cells may represent an anti-tumor response, although on one occasion a low frequency clone was transformed and expanded after culture. Metastatic tumor clones were detected in the blood early during infection and dominated the circulating T cell repertoire, leading to MDV associated immune suppression. We also demonstrated that the tumor-infiltrating CD8+ T cell response was dominated by large oligoclonal expansions containing both “public” and “private” CDR3 sequences. The frequency of CD8+ T cell CDR3 sequences suggests initial stimulation during the early phases of infection. Collectively, our results indicate that MDV driven tumors are dominated by a highly restricted number of CD4+ clones. Moreover, the responding CD8+ T cell infiltrate is oligoclonal indicating recognition of a limited number of MDV antigens. These studies improve our understanding of the biology of MDV, an important poultry pathogen and a natural infection model of virus-induced tumor formation.

Induction of lymphomas by inoculation of Marek's disease virus-derived lymphoblastoid cell lines: prevention by CVI988 vaccination

“…and 5?-CACGGTCGACGATGAGAACGCTACCCTGAGATGC-3?, respectively, with a common Cb reverse primer of 5?-ACAGGTC-GACGTACCAAA GCATCATCCCCATCACAA-3? (Mwangi et al, 2010(Mwangi et al, , 2011.…”

“…A number of MDV-derived lymphoblastoid cell lines have been developed by in vivo and in vitro passage of primary lymphomas over the years (Akiyama & Kato, 1974;Nazerian, 1975Nazerian, , 1987Nazerian et al, 1977;Stephens et al, 1980;Payne et al, 1981;Coleman & Schierman, 1982;Mwangi et al, 2011). Most of these cell lines produce infectious virus, while some such as RP-1, referred to as non-producer cell lines, have lost the capability to produce infectious virus (Stephens et al, 1976;Nazerian et al, 1977).…”

“…The present study was undertaken to test the suitability of our recently developed TCRb repertoire analysis tools (Mwangi et al, 2010(Mwangi et al, , 2011 for tracking and characterization of tumours resulting from inoculation of the lymphoblastoid cell lines derived from RB-1B and pRB-1B5 viruses between inbred P-line (MHC B 19 /B 19 ) hosts. We also investigated the efficacy of CVI988 vaccine in prevention of tumour development in this adoptive cell transfer model.…”

Morphology of immune organs after very virulent plus strain of Marek’s disease virus infection in vaccinated hens

“…Transformed T lymphocytes subsequently lead to the development of gross lymphomatous (proliferative or less often inflammatory) lesions in visceral organs with accompanying immunosuppression (Burgess and Davison 1999). Recent studies presented by Mwangi et al (2011) indicated that MDV driven lymphomas are dominated by highly restricted number of CD4 + clones indicating monoclonal or oligoclonal origin of these tumors. The switch from cytolytic to latent phase occurs about one week post infection (Schat and Xing 2000).…”

“…The CTL were characterized as CD8 + TCR2 + cells, while the CD4 + and TCR1 + cells are not important for the elimination of MDV antigen-expressing cells (Omar and Schat 1997). The responding CD8 + T cell infiltrates are oligoclonal indicating recognition of a limited number of MDV antigens (Mwangi et al 2011). The specific humoral immune response includes production of antibodies against MDV glycoproteins such as gB, gE, and gI.…”