Increased immunogenicity of a spontaneous variant clone of the 13762A XXXX mammary @entity420 .

@entity5 @entity189 @entity2357 @entity3 @entity35 @entity204 @entity420
The 13762A @entity35 mammary @entity420 is weakly immunogenic and spontaneously metastasizes to regional lymph nodes and lungs. A clone (18A) was isolated from the parental @entity5 , which grew for 3 weeks in normal F344 @entity35 , forming @entity5 up to 2-3 cm and some nodal @entity3 , and then completely regressed. Pretreatment of recipient @entity35 with 450 rad permitted progressive growth and @entity204 due to @entity3 . The behavior of 18A has been stable during a period of 120 days in continuous culture or for 6 in vivo passages in irradiated @entity35 . Regression of 18A was associated with intense @entity5 mononuclear leukocytic infiltration, whereas parental @entity5 of the same size recruited few leukocytes. @entity2357 occurred when 18A cells were placed intradermally, sc, or im, but iv injections were not rejected. Parental @entity5 grew progressively at all sites. Regressor @entity35 were specifically immune to challenge with both 18A and parental @entity5 but not to an unrelated @entity189 (R3230AC). Irradiated 18A @entity5 cell vaccines protected recipients against challenge with parental @entity5 , but similar vaccines of irradiated parental @entity5 cells were ineffective. The systemic adoptive transfer of immune lymphocytes more strongly inhibited the growth of established (7 days) 18A than parental @entity5 . It was concluded that the parental 13762A @entity5 contained stable variants that were significantly more immunogenic and more susceptible to immune attack than the parental @entity5 . Such variant @entity5 lines may be useful in the study of the host response to @entity3 .
