Expression of fetal antigens by normal human skin cells grown in tissue culture

Normal human sera are capable of causing complement-mediated lysis of normal human skin cells grown in tissue culture. This lytic reactivity can be completely removed by absorption with first trimester fetal tissue. Absorption with a variety of normal adult human tissues including lymphocytes, decidua, skin, and muscle are incapable of absorbing reactivity. Absorption of reactivity by fetal tissue is specific and not due to the introduction of anti-complementary or other nonspecific factors, as evidenced by the inability of simultaneous fetal absorption to remove reactivity from antisera with specificity for HLA antigens. Similarly, absorption of lytic sera with fetal calf serum proteins was incapable of removing reactivity against normal cells in tissue culture. It thus appears that normal human cells in tissue culture express antigens shared by the first trimester human fetus, but not present on a variety of adult human tissues. This "neoantigen" present on normal human cells when grown in tissue culture is a potential source of confusion and must be accounted for in searching for human tumor-specific antigens utilizing tissue culture cells.

Axillary lymph node biopsy

We describe a technique that facilitates excisional biopsy of the axillary lymph nodes. The arm is suspended anterior to the chest in an adducted position that displaces the pectoralis major muscle medially and positions the axillary lymph nodes immediately deep to the hair-bearing area of the skin. This position permits biopsy of the lymph nodes with a relatively short incision and a minimum of dissection.

Extrapulmonary lesions of Streptococcus pneumoniae infection in guinea pigs

A retrospective study of extrapulmonary disease in 17 guinea pigs with Streptococcus pneumoniae infection showed the most common to be either chronic active or acute fibrinopurulent pericarditis, pleuritis or peritonitis, or all three. In periparturient females the uterus was commonly affected. Hepatic and adrenal necrosis, splenitis, otitis media, encephalitis, lymphadenitis and ovarian abscesses also occurred. There were gram-positive diplococci in all lesions and Strep. pneumoniae, most often type 19, was cultured from tissues of 11 guinea pigs.

Cross-reacting antigens in chemically induced sarcomas are fetal determinants

Serologic cross-reactivity has been demonstrated among three MCA-induced sarcomas in C57BL/6N female mice (MCA-2, MCA-3, and MCA-12) with a microcytotoxicity assay. Serum from mice bearing MCA-3 tumor was cytotoxic to both MCA-2 and MCA-3 tumor cells at a titer of 1:8. Sequential absorptions of this serum with syngeneic embryo cells completely eliminate cytotoxicity against MCA-2 cells without affecting the cytotoxic titer against MCA-3 cells. Serum hyperimmune to the MCA-3 tumor reacted with MCA-3, MCA-2, and MCA-12 tumors. Absorption of this serum with embryo cells eliminated cytotoxicity against MCA-2 and MCA-12 cells, but was incapable of lowering the titer against MCA-3 cells below 1:40. Similarly, serum hyperimmune to MCA-2 tumor was lytic to MCA-2, MCA-3, and MCA-12 before absorption, but was lytic only to MCA-2 cells after absorption with sygeneic embryo cells. Thus, the in vitro cross-reactivity between MCA-induced sarcomas is due to a common fetal antigen(s), which is distinct from the individual tumor-specific antigens of each tumor. Since these tumors do not exhibit cross-reactivity in in vivo challenge experiments, it appears that this fetal antigen is not responsible for in vivo immune protection.

Serologic identification of multiple tumor-associated antigens on murine sarcomas

The humoral immune response to two transplanted chemically induced murine sarcomas (MCA-2 and MCA-3) was studied in C57BL/6N mice. These tumors were immunogenic as evidenced by tumor amputation and rechallenge experiments, and no cross-reactivity between them was observed in in vivo challenge experiments. Utilizing a complement-dependent microcytotoxicity assay, we detected antibody to both MCA-2 and MCA-3 in the sera of animals bearing MCA-3 as well as after tumor removal. The sera of animals hyperimmunized to MCA-3 (MCA-3HI) was also cytotoxic in high titer to both MCA-2 and MCA-3 (50% cytotoxicity titers of 1:80 and 1:320, respectively). Sequential absorptions of sera from animals bearing MCA-3 and MCA-3HI sera with fresh MCA-2 cells completely removed activity against MCA-2 but retained reactivity to MCA-3. Sequential absorptions with fresh MCA-3 cells produced stepwise reductions of activity against both tumors, whereas absorption with normal cells produced no loss of activity against either tumor. Thus both specific and cross-reactive antigens were expressed on the surfaces of MCA-3 cells. Only the specific tumor antigen appeared to be involved in in vivo protection against tumor challenge.

Myocarditis of probable viral origin in chickens

Severe nonsuppurative myocarditis with Feulgen-positive intranuclear inclusions in six adult White Leghorn chickens is described. Livers of three birds had mild to moderate centrilobular coagulative necrosis, with no inclusions. The myocardial intranuclear inclusions contained a large number of 18-to-20-nm particles; these are compared with members of the family Parvoviridae.

Thymomas in domestic animals

A retrospective study of 15 thymomas in domestic animals showed four animals had antemortem signs of dyspnea and grossly visible lumps in the thoracic inlet. The neoplasms were single, multilobulated, encapsulated masses in the anterior mediastinum or thoracic inlet. Cells with clear cytoplasm comprised the bulk of two canine thymomas, whereas the remaining neoplasms had a mixed population of ovoid and spindle-shaped cells. There were lymphocyte populations of varying density in all thymomas. Three thymomas contained structures similar to hyalinized cells and Hassall's corpuscles of normal thymus. Metastatic lesions were not seen but there were implantations on the pericardium in one cat. There was capsular invasion in the ovine thymomas.

The sexual behaviour of the blowfly, Protophormia terrae-novae R.-D

Abstract

In P. terrae-novae the male courtship behaviour begins with a run towards the female followed by mounting, orientation, and copulation. Male sexual activity begins on the second day after adult emergence if supplied with a solution of "Marmite" yeast extract and milk, sugar, and water. No reactions to a volatile sex attractant could be demonstrated from either sex. Other males are equally effective as females in eliciting "encounters" from sexually active males, and the encounter rate of males in isolated all male cultures is the same as that of males in the presence of attractive females. Though attractive females do not affect the male behaviour before contact they elicit an increased chance of completion of the pattern after encounter, whereas bouts with other males tend to break off in the early stages of courtship. Sexual behaviour directed towards newly emerged individuals of either sex is inhibited relative to that directed towards other sexually active males. The males from mixed-sex cultures gradually become attractive to other males, which respond to them as if they were attractive females. This may be due to their contamination with a female pheromone of the "mounting stimulant" type. Though males fed only on sugar and water showed a vastly reduced rate of sexual activity, their mechanism of sex discrimination remained unimpaired. In cultures with active males, newly emerged females become attractive and mate on the second day after adult emergence. About 4% of the attacks by males on pairs in copula result in a clnange of copulating male. After copulation females reject any further attention from males by horizontal vibration of their wings across the abdomen. This reduces the duration of mounting and prevents genital contact, otherwise mated females are as attractive as virgins. The female vibration response is elicited mainly on mounting, especially after orientation, but never before contact by the male. Males reject courtship with a "pushing" of the hind legs as in cleaning. This operates when a mount persists, and though the chances of orientation and genital extension are reduced the chance of mounting is not.