Propagation and assay of virulent and attenuated JMV Marek's disease‐associated tumour cells

Abstract

SUMMARYJMV tumour cells were shown to cause a lethal lymphoblastic leukaemia in young chickens as well as in chicken embryos. The incubation period was very short but dose-dependent. Chickens died in 4 to 12 days, embryos in 7 to 14 days, after inoculation. Embryo-passaged attenuated JMV (JMV-A) caused the same lesions in embryos as virulent JMV. The dose-response relationship depended on the route of inoculation and on the quality of the tumour cell preparation. Intramuscular (i.m.) inoculation of leukaemic blood or embryo lymphoblasts provided the most satisfactory response. Intraperitoneal (i.p.) inoculation and lymphoblastic chicken spleens as a source of JMV were definitely less suitable. The doseresponse curves obtained in yolk sac-inoculated embryos were similar to the curves obtained by i.m. inoculation of chickens. Only 4 to 10 lymphoblasts were needed per lethal dose (50%) in chickens and 50 to 80 in embryos.The pathogenicity and antigenicity of JMV and JMV-A were strictly cellassociated. No Marek's disease (MD) virus or any other avian virus could be detected, either by various virus isolation procedures, or by serological methods. Contact transmission of JMV to other chickens did not occur.Antibodies against surface antigens on JMV lymphoblasts were detected in JMV and JMV-A chicken hyperimmune sera. These sera reacted against MD lymphoblastoid cell lines (HPRS-1 & 2, MSB-1) as well as MSB-1 antiserum, but all sera reacted also against thymus lymphocytes from normal chickens. The results of absorption tests suggested that the surface antigens of JMV lymphoblasts and of the tested cell lines were not identical. The majority of tumour cell surface antigens appeared to represent genetically specific histocompatibility or lymphocyte antigens. A common MD tumourassociated surface antigen (MATSA) could not be identified serologically (FA test) on the tumour cells studied.

Cross‐protection between JMV Marek's disease‐derived tumour transplant, Marek's disease and Turkey herpesviruses

“…Previous experiments in our laboratory (Bülow and Weiland, 1977) have shown that cell-free preparations of JMV intended for use in cross-immunisation studies were completely ineffective. Witter and his group concluded from their results (Witter et al, 1975 ;Stephens et al, 1976) that JMV lymphoblasts carried a surface antigen closely related or identical to MD tumour-associated surface antigen (MATSA).…”

“…Marek's disease (MD)-derived tumour cells capable of causing a lethal lymphoblastic leukaemia in chickens have been designated as JMV (JM variant) by Sevoian (1967). Studies designed for the biological characterisation of JMV have revealed that virulent as well as attenuated JMV lymphoblasts (JMV, JMV-A) were lacking in rescuable virus (Witter et ai, 1975;Stephens etal, 1976;Bülow and Weiland, 1977). This is inconsistent with the results of other authors who found Marek's disease virus (MDV) or an unspecified herpesvirus associated with JMV (Hamdy and Sevoian, 1973;Hong and Sevoian, 1974;Shieh and Sevoian, 1974;Spencer et al ,1974Spencer et al , , 1976Yoon andKenyon, 1975;Yoon et al, 1976).…”

Further characterisation of the CVI 988 strain of Marek's disease virus

“…Chickens and embryos were from a flock of Rhode Island Red (RIR) chickens which are genetically susceptible to MD and are specific pathogen-free for all common avian viruses (Bülow and Weiland, 1977).…”

Serologische Charakterisierung von Tumorzellinien der Marekschen Krankheit*

“…Die Kultivierung der Zellinien RPL-1, MSB-1, HPRS-1 und HPRS-2, die Gewinnung von JMV-Lymphoblasten aus Kuken oder Embryos und die Herstellung von Huhner-Hyperimmunseren gegen JMV sind in einer friiheren Arbeit beschrieben worden (BULOW u. WEILAND, 1977). Zur Herstellung von Antiseren gegen Zellen der Linien RPL-1, MSB-1 und HPRS-2 wurden Kaninchen dreimal in Abstanden von 14 Tagen mit 2-4 X lo8 Zellen i. v. immunisiert und 7 Tage nach der letzten Immunisierung entblutet.…”