Allogeneic pregnancy in B-lymphocyte deprived CBA/Ca mice--effects on maternal lymphoid organs and fetal survival.

A number of female CBA/Ca (H2-k) mice were injected with rabbit-anti mouse IgM every 2 days throughout their life cycle in order to prevent their development of immunocompetent B-lymphocytes. The efficiency of the anti IgM-treatment was good in the group of mice used, and all experimental mice almost completely lacked 1) surface Ig-staining cells (immunoperoxidase ABC method), 2) serum IgG (ELISA technique), and 3) Ig-secreting cells (protein A plaque assay). All experimental mice contained a functioning T-cell pool, as recorded in vitro by conA-stimulation and one-way MLC. At an age of 40-60 days these mice were allowed to mate allogeneically with C57/Bl (H-2b) males. No harmful effects of the anti-IgM treatment on the first pregnancy cycle were found, and B-cell deprived mice delivered as many healthy litters as did the controls. It was also observed that the enlargement of the spleen and uterus-draining nodes was of the same magnitude in both experimental and control mice at the end of the first pregnancy.

Allopregnancy in B-cell deprived C57/BL mice--an investigation focusing on the relationship between survival of the fetuses and anti-paternal immune activity of the mothers.

C57/B1 female mice (haplotype H2-b) were treated throughout their life cycles with rabbit anti-mouse IgM antibodies in order to remove all maturing B-lymphocytes. At an age of 40 days the B-cell-deprived mice and the corresponding controls were allowed to mate with CBA/Ca males (haplotype H2-k). Four groups of allopregnant animals were investigated: (A) mice not subjected to further treatment, which were allowed to pass through a first pregnancy, (B) mice not subjected to further treatment, which were allowed to pass through a first and second pregnancy, (C) mice immunized with paternal cells prior to mating and then allowed to pass through a first pregnancy, (D) mice which during their first pregnancy were given transfusions of anti-paternal lymphocytes obtained from hyperimmune virgin donors. All animals were dissected on the calculated day for parturition (or the first day that abortions or resorptions were detected). On conclusion of the experiments, the efficiency of the anti-IgM treatment was defined for each mouse, using three different methods (ELISA for detection of serum IgG, immune staining for detection of surface Ig-carrying cells, and the protein A plaque assay for detection of Ig-secreting cells). The T-cell function was recorded in vitro by ConA responsiveness. In addition, control animals were assayed for anti-paternal serum antibodies. In experiments (A), (B) and (C), B-cell-deprived mice and corresponding controls were equally successful in passing through pregnancy, having fairly similar litter sizes and resorption frequency. In group (D), however, some of the anti-IgM-treated mice resorbed all her fetuses. Those that gave birth at on schedule had a resorption frequency and litter size fairly similar to those of the controls.

Humoral immune activity in CBA/Ca mice during late pregnancy and the post-partum period.

Syngeneically mated CBA/Ca mice were used to measure "spontaneous" immunoglobulin (Ig) secretion in the Peyer's patches (PP), spleen and the para-aortic lymph nodes (PALN), employing a protein A plaque assay, during the latter part of pregnancy and in the post-partum period. The lactating and non-lactating females were compared with respect to humoral immune activity (plaque-forming cells) and serum Ig levels (ELISA technique). The pregnancy-induced weight changes in some lymphoid organs and the elevation in the number of plaque-forming cells in spleen (IgG and IgM PFC), PALN (IgG and IgM PFC) and the PP (IgA PFC) lasted longer in the lactating than in the non-lactating mice (owing to hormonal differences). A very strong decrease in serum IgG was observed during pregnancy and after parturition IgG levels remained depressed longer in lactating than in non-lactating mice. Interest has been focused on IgA in the study and this has been discussed as well as the possible reasons for the increased turnover of maternal serum Ig (especially IgG).

Effects of pseudopregnancy on immunoglobulin-secreting cells in mice.

Pregnant mice characteristically show elevated numbers of immunoglobulin-secreting cells in their enlarged spleen and para-aortic lymph nodes. A comparative study of pseudopregnancy and syngeneic pregnancy in CBA/Ca mice was made to evaluate the role of maternal hormones in the induction of these changes. To induce pseudopregnancy, CBA/Ca female mice were mated with vasectomized males, the duration of pseudopregnancy induced in this way is 8-10 days. Serum progesterone levels were monitored periodically throughout pseudopregnancy using RIA technique. Changes were recorded in weight of the thymus, spleen and para-aortic lymph nodes, levels of serum IgG and IgM (ELISA-technique), and content of splenic IgG- and IgM-secreting cells (protein A plaque assay). Thymus involution was observed in pregnant and pseudopregnant mice. Patterns of change in the weight of the spleen and the para-aortic lymph nodes (PALN) were similar in pregnant and pseudopregnant mice until day 8. Ig-secretion in the spleen increased slightly day 5-8 in both pregnant and pseudopregnant mice, but to a lesser extent in the latter. No differences were observed in serum Ig levels between the two groups until day 8. A marked decrease in serum IgG levels and, to some extent, IgM levels between days 8 and 12 was observed in pregnant animals.

An investigation of allogeneic pregnancy in multiparous mice subjected to in vivo depletion of CD8 (Ly2)-positive lymphocytes by monoclonal antibody treatment.

Adult thymectomized C57/Bl (H-2b) and DBA/1 (H-2q) female mice were subjected to treatment with rat anti-mouse CD8 and mouse anti-rat Ig (kappa) prior to entering their third pregnancy with CBA/Ca (H-2k) males. The treatment protocol drastically reduced the number of CD8 (Ly2)-carrying lymphocytes (T-cytotoxic/suppressor phenotype) in the spleen and para-aortic lymph nodes, as assessed by immuno-staining. All mice were investigated on day 18 of their third gestation. The following data were collected from experimental and control groups: (1) resorption frequency, (2) weight of the placenta, fetuses, spleen and para-aortic lymph nodes, (3) immunohistochemical analysis of maternal lymphoid tissues, (4) level of anti-paternal IgG serum antibodies, (5) content of "background" IgM and IgG-secreting cells in spleen and para-aortic lymph nodes. Neither the resorption frequency nor placental/fetal weight was affected by anti-CD8 treatment. However, the formation of anti-paternal antibodies was enhanced in anti-CD8 treated C57/Bl mice.

Foscarnet for pre-emptive therapy of CMV infection detected by a leukocyte-based nested PCR in allogeneic bone marrow transplant patients.

Fifteen allogeneic BMT patients in a phase II study were given foscarnet 60 mg/kg twice daily for 14 days as pre-emptive therapy against CMV disease. CMV infection was diagnosed by a leukocyte-based nested PCR. All 15 patients were evaluable for toxicity. One patient did not fulfill the inclusion criteria of two consecutively positive CMV PCR tests and therefore was not evaluable for efficacy. Thus, 14 of 15 patients were evaluable for development of CMV disease. None of the patients developed CMV disease and all 14 assessable patients had a negative CMV isolation at the end of therapy. None of the 15 patients had to discontinue therapy due to toxicity. Six patients reported mild gastrointestinal disturbances, three patients headaches, and three patients mild urethritis or hemorrhagic cystitis. Serum-electrolyte disturbances were common including abnormal magnesium, potassium and calcium levels. Two patients developed mild serum-creatinine increases requiring adjustment of the foscarnet dosage according to protocol. We conclude that a dosage of foscarnet of 60 mg/kg given twice daily seems to be safe and effective in preventing CMV disease in allogeneic BMT recipients. A study comparing foscarnet and ganciclovir is indicated.