Immunoglobulin isotypes in plasma cells of normal and athymic mice

Human breast cancer cell line xenografts as models of breast cancer. The immunobiologies of recipient mice and the characteristics of several tumorigenic cell lines

The ability to maintain and study human tissues in an in vivo environment has proved to be a valuable tool in breast cancer research for several decades. The most widely studied tissues have been xenografts of established human breast cancer cell lines into athymic nude mice. Human breast tumor xenografts provide the opportunity to study various important interactions between the tumor and host tissues, including endocrinologic, immunologic, and tumor-stroma interactions. The nude mouse is not the only immune-deficient recipient system in which to study xenografts. Additional single and combined mutant strains have been used successfully, including mice homozygous for the severe combined immune deficiency mutation (scid), both the beige (bg) and nude (nu) mutations in combination (bg/nu), and mice bearing the combined bg/nu/xid mutations. The differing immunobiologies are discussed, with particular reference to the immunobiology of breast cancer, as are the characteristics of several of the more frequently utilized breast cancer xenografts and cell lines. The ability of several endocrine treatments to modulate effectors of cell mediated immunity, e.g., estrogens and antiestrogens, and the effect of site of inoculation on tumor take and metastasis, also are described.

Comparative abilities of athymic nude mice and severe combined immune deficient (SCID) mice to accept transplants of induced rat mammary carcinomas: enhanced transplantation efficiency of those rat mammary carcinomas that have elevated expression of neu oncogene

Grafts of primary carcinogen (DMBA)-induced mammary carcinomas from Sprague-Dawley rats have a poor transplantation efficiency in athymic nude mice. Further compromising these mice immunologically via whole-body irradiation and/or splenectomy, or the administration of hormonal growth factors (estrogen and progesterone) to these mice, did not significantly alter transplantation efficiency. Use of strains of mice that are more immune-impaired than the athymic nude mouse, i.e., the athymic nude-beige-XID mouse (T-cell and LAK-cell deficient) or mice with severe combined immune deficiency (SCID) (which lack functional T cells and B cells) also failed to improve transplantation efficiency. In contrast, transplantation efficiency was sharply increased when primary neu-induced rat mammary carcinomas from female Sprague-Dawley rats were used. These mammary carcinomas, unlike the DMBA-induced rat mammary carcinomas, have a very high level of expression of neu; transplantation of these tumors to either athymic nude mice or SCID mice was considerably more efficient. Thus, these data provide evidence that enhanced expression of neu confers heightened efficiency in the transplantation of primary rat mammary carcinomas to immune-deficient mice (athymic-nude or SCID). Increased neu expression was a greater determinant than more compromised immune states in the transplantation of these rat mammary carcinomas. This biological characteristic of neu expression in mammary carcinomas provides new, additional insight into the importance of this oncogene in mammary tumorigenic processes and may explain, at least in part, the reported inverse relationship between human breast carcinoma neu expression and patient prognosis.

T cell populations in the lacrimal gland during aging

The present study examined the influence of age and gender on T cell populations in the lacrimal gland. Lacrimal (exorbital) glands were obtained from male and female rats at 19 days (pre-puberty), 9 weeks (adult) and 14 months (mid-life) of age and tissues were processed for T cell subset identification. In females, the density of total (W3/13+ and OX 19+), helper/inducer (W3/25+) and suppressor/cytotoxic (OX 8+) T cells underwent a significant increase in tissues from before, to after puberty. Following this rise, the density of all T cell populations decreased in glands from young adult to midlife females. This pattern of accumulation contrasted with the T cell profile presented by glands from males: T cell densities appeared unaffected from 19 days to 9 weeks of age, and then either declined (OX 19+, W3/25) or remained unchanged (W3/13+, OX 8+) in tissues of 14 month rats. An influence of gender on the distribution of T cells was also apparent if results were corrected for age-associated variations in lacrimal gland weight. Thus, the absolute number of all T cell populations rose dramatically in glands of both sexes from pre- to post-puberty. However, from 9 weeks to 14 months of age, the total content of W3/13+, OX 19+, W3/25+ and OX 8+ lymphocytes decreased 2-fold in glands of females, but did not vary in tissues of males. Of interest, the number of W3/25+ and OX 8+ cells was analagous in all age groups examined. Moreover, the combined total of W3/25+ and OX 8+ cells was greater than that of W3/13+ or OX 19+ cells at every age.(ABSTRACT TRUNCATED AT 250 WORDS)

Transplantation of human breast epithelia to mammary-gland-free fat-pads of athymic nude mice: influence of mammotrophic hormones on growth of breast epithelia

Normal human breast tissue was enzymatically dissociated and the cells were injected into the gland-free fat-pads of athymic nude mice. Within 30 days, small, spherical, duct-like epithelial elements (organoids) formed in 68% of the fat-pads inoculated (0-23 organoids/fat-pad). Short-term (30-day) treatment of the host mice with mammotrophic hormones [secretions from a chorionic, soamto-mammotrophin-secreting transplantable human choriocarcinoma (JEG-3), secretions from a prolactin- and growth-hormone-secreting transplantable rat pituitary tumor (GH3), estrogen and/or progesterone] and/or cAMP inducers (cholera toxin) significantly (p less than 0.05) increased the size of the human breast organoids but did not increase organoid number or induce extensive and expansive growth (extensive duct elongation and branching) of these structures. Such treatments induced intense proliferation of the host mouse mammae resembling that which occurs during late pregnancy. The results of this study, therefore, provide evidence that normal human breast epithelium can be readily accepted by and maintained in the gland-free fat-pad of the athymic nude mouse, and the epithelium, within 30 days, forms spherical duct-like structures (organoids). The human breast organoids are hormone-responsive, as they respond to a mammotrophic growth stimulus by an increase in size. The failure of the human breast organoids to grow expansively in the gland-free fat-pad of this immunologically deficient mouse does not appear to be due to the absence of an appropriate hormonal growth stimulus.

Frequency analysis of the antibody specificity repertoire of mitogen-reactive B cells and "spontaneously" occurring "background" plaque-forming cells in nude mice

The antibody specificity repertoire of lipopolysaccharide (LPS)-reactive B cells has been determined in the spleens and bone marrow (BM) of C57BL/Ka athymic nude mice using a limiting dilution culture system that allows the growth and development of every LPS-reactive B cell into a clone of IgM-secreting cells. In addition, the numbers of "spontaneously" occurring ("background") IgM-, IgG-, and IgA-secreting cells as well as the "background" IgM antibody specificity repertoire has been assessed in spleens and BM. The frequencies of antigen-specific LPS-reactive B cells of C57BL/Ka nude and thymus-bearing mice showed a great similarity and ranged from 1 in 1000 to 1 in 2500 for sheep red blood cells (SRBC), horse red blood cells (HRBC), and goat red blood cells (GRBC), from 1 in 10 to 1 in 25 for 5-iodo-3-nitrophenyl-coupled (SRBC), from 1 in 15 to 1 in 150 for 4-hydroxy-3,5-dinitrophenyl-coupled SRBC, and from 1 in 70 to 1 in 140 for 2,4,6-trinitrophenyl-coupled SRBC. The specificity repertoire of the "background" IgM-secreting cells differed from that of age-matched thymus-bearing controls and was different in young and old C57BL/Ka nude mice. Within the limitations of having assessed only a minor fraction of the total B-cell antibody specificity repertoire and supposing that nude mice are largely devoid of functional T cells, the data presented suggest that the generation of the specificity repertoire of newly-formed B cells is hardly or not affected by T cells. On the other hand, T cells do affect the expression of the established repertoire, represented by "background" immunoglobulin-secreting cells.

Distribution of immunoglobulin-containing cells in normal and neonatally thymectomized rats

The distribution of immunoglobulin-containing cells (ICC) of the immunoglobulin A (IgA), IgG, and IgM isotypes was examined in various lymphoid and secretory tissues of rats. The effect of neonatal thymectomy of rats on T cells, B cells, and ICC in these tissues was determined by immunofluorescence. The results showed that although T cells were severely depleted in both lymphoid and secretory tissues of the thymectomized (Tx) rats, Tx and normal rats showed comparable numbers of B cells staining for IgA, IgG, and IgM. After neonatal thymectomy, IgA ICC in both lymphoid and secretory tissues were significantly decreased. However, the Tx rats exhibited a compensatory increase in IgM ICC in the identical tissues. Local injection of normal and Tx rats with Streptococcus mutans 6715 resulted in an increase in all isotypes of ICC in the secretory tissues. Although the primary increase in normal rats was due to IgA ICC, Tx rats exhibited the greatest change in the number of IgM ICC.