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Induction of lymphoma in BALB/c mice by Rowson‐Parr virus (RPV)
Author(s) -
Carter R. L.,
Chesterman F. C.,
Rowson K. E. K.,
Salaman M. H.,
Wedderburn N.
Publication year - 1970
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910060217
Subject(s) - lymphoma , hyperplasia , spleen , neoplasm , pathology , reticulum , biology , medicine , endoplasmic reticulum , immunology , biochemistry
The long‐term pathological effects of Rowson‐Parr virus (RPV), injected intravenously into 84 young adult BALB/c mice, are described. In the main experiment, 70 test mice and 30 uninjected control mice were examined serially between 4 and 48 weeks. A second group of 14 injected animals were allowed to live out their life‐span. Four stages in the host response have been defined. Splenic hyperplasia predominates in Stages I and II: there is initially a short‐lived phase of moderate splenic enlargement and reactive hyperplasia (Stage I) which partly resolves, to be followed by a persistent period of slight splenomegaly and low‐grade (non‐specific) reactive hyperplasia (Stage II). Neoplastic changes (Stages III and IV) developed in almost 45% of test mice in the serial study. In most instances, the neoplastic process appears to arise in reticulum cells in the Malpighian follicles of the spleen and is initially confined to these structures (Stage III). Later (Stage IV) there is progressive replacement of the splenic pulp and increasing involvement of lymph nodes, liver and thymus; some animals develop a terminal leukaemia. A similar reticulum‐cell neoplasm was found in many of the RPV‐infected mice which were allowed to live out their life‐span; none of these animals survived for more than a year after infection. Four RPV‐infected mice developed lymphomas and leukaemias of other histological types. No reticulum‐cell neoplasms were found in the uninjected control animals. Certain features of the reticulum‐cell lymphoma associated with RPV are discussed. Emphasis is directed to two features; (1) the biphasic nature of the host response with respect to time, the lymphoma being preceded by long‐sustained reactive changes; and (2) the finding that reactive and neoplastic changes arise sequentially in the same organ, and perhaps involve the same cell‐type—splenic reticulum cells. In contrast to findings in several other murine lymphomas, the thymus is not apparently involved until late in the disease. It is clear that RPV can no longer be regarded as “a virus of minimal pathogenicity”.