Antibody formation in mouse bone marrow. VII. Evidence against the migration of plaque-forming cells as the underlying cause for bone marrow plaque-forming cell activity: a study with parabiotic mice

Analysis of 15 patients with systemic lupus erythematosus manifesting with negative immunofluorescence anti-nuclear antibodies after treatment

The purpose of this study was to investigate the clinical and laboratorial characteristics of patients with systemic lupus erythematosus (SLE) manifesting with negative immunofluorescence anti-nuclear antibodies (IFANA) after treatment for the better understanding of negative conversion of IFANA. Demographic characteristics, clinical and laboratory data of hospitalized SLE patients between March 2006 and May 2011 were retrospectively reviewed. Fifteen cases with negative IFANA were identified in 960 patients. All of the 15 patients were severe, 11 patients manifested with nephritic range proteinuria and hypoalbuminemia, 8 patients were complicated with severe infection and all of the patients had been treated with glucocorticoid and immunosuppressant. Anti-ENA antibodies were positive in 4 of 15 patients. Eight patients died after average 1-year follow-up. Collectively, negative IFANA is mainly attributed to nephritic-range proteinuria; and large-dose glucocorticoid, immunosuppressant and severe infection are also important factors for negative IFANA. Antinuclear antibody can be detected in some SLE patients with negative IFANA by changing the detection method and titer. Negative conversion of IFANA often indicates unfavorable prognosis for severe patients.

Functional memory B cells and long-lived plasma cells are generated after a single Plasmodium chabaudi infection in mice

Antibodies have long been shown to play a critical role in naturally acquired immunity to malaria, but it has been suggested that Plasmodium-specific antibodies in humans may not be long lived. The cellular mechanisms underlying B cell and antibody responses are difficult to study in human infections; therefore, we have investigated the kinetics, duration and characteristics of the Plasmodium-specific memory B cell response in an infection of P. chabaudi in mice. Memory B cells and plasma cells specific for the C-terminal region of Merozoite Surface Protein 1 were detectable for more than eight months following primary infection. Furthermore, a classical memory response comprised predominantly of the T-cell dependent isotypes IgG2c, IgG2b and IgG1 was elicited upon rechallenge with the homologous parasite, confirming the generation of functional memory B cells. Using cyclophosphamide treatment to discriminate between long-lived and short-lived plasma cells, we demonstrated long-lived cells secreting Plasmodium-specific IgG in both bone marrow and in spleens of infected mice. The presence of these long-lived cells was independent of the presence of chronic infection, as removal of parasites with anti-malarial drugs had no impact on their numbers. Thus, in this model of malaria, both functional Plasmodium-specific memory B cells and long-lived plasma cells can be generated, suggesting that defects in generating these cell populations may not be the reason for generating short-lived antibody responses.

Malaria causes considerable human suffering resulting from associated high mortality, morbidity and reduced economic productivity in endemic areas. Current control methods are thwarted by a multiplicity of problems including rapidly developing resistance for anti-malarial drugs and insecticide-treated nets, and huge costs and hence poor coverage with bed nets in poor countries. Understanding the basis of the inefficiency of immunity to malaria in childhood will greatly aid the search for effective vaccines, which together with drugs and vector control, will be essential in the drive to eliminate malaria. Because of the strong evidence associating anti-malarial antibodies with anti-parasitic and anti-disease effects, vaccines inducing protective long-lasting antibody responses are attractive. However, it has been suggested that antibody responses to some Plasmodium antigens may be not long-lived. It would be important to determine whether long-lived plasma cells and memory B cells are generated after a malaria infection; however, these studies are difficult to perform in humans. Therefore we investigated the kinetics, duration and characteristics of the two cell types responsible for long-term antibody production in a mouse model of malaria. We show here that malaria-specific memory B cells and plasma cells are still detectable more than eight months after infection, and that both long-lived malaria-specific antibody-secreting cells and functional malaria-specific memory B cells can be made after a single infection.

Recruitment of lymphocytes to the lung through vaccination enhances the immunity of mice exposed to irradiated schistosomes

The effector mechanism, which operates against challenge parasites in the lungs of C57BL/6 mice vaccinated once with irradiated cercariae of Schistosoma mansoni, is mediated by CD4+ T helper lymphocytes. However, adoptive transfer of immunity from vaccinated donors to naive recipients by using sensitized T cells has not proved successful. One explanation may be that the recruitment of sensitized T lymphocytes to the lungs by vaccinating parasites to arm that organ is not reproduced by transfer protocols. We have used the technique of parabiosis, as a means of adoptive transfer, to demonstrate the relevance of pulmonary T cells to protection. Sensitized and naive partners were joined surgically for a 28-day period, coincident with priming of the immune system. A vascular union rapidly developed, and sensitized T cells were detected in the spleens of the naive partners. When parabionts were challenged percutaneously 10 days after separation, the level of immunity transferred to the naive partners was approximately two-thirds that of their vaccinated counterparts. The naive partners, unlike the vaccinated animals, did not recruit lymphocytes to the lungs during the priming period. In contrast, after percutaneous challenge, schistosome-specific lymphocytes were recruited to the lungs of both separated parabionts. The importance of lymphocytes recruited to the lungs during the primary response was revealed by an intravenous challenge with lung schistosomula; this eliminates the opportunity for secondary immune responses prior to parasite arrival in the lungs. In this situation, the vaccinated partners showed 47% immunity while the naive partners were not protected. We conclude that the presence of specific T cells in the lungs at the time of challenge confers a significant advantage, permitting a more effective recall response than in animals lacking such resident cells.

Improved plaque production for short-term bone marrow and fetal liver cultures

The addition of 0.5% globulin-free (GF-BSA) or 0.5% delipidated BSA (D-BSA) to short-term murine bone marrow (BM) (cultures) increased the number of plaque-forming cells (PFC) responding to trinitrophenylated lipopolysaccharide (TNP-LPS) 2-5-fold (1.1 X 10(4)-2.7 X 10(4) PFC per 10 X 10(6) nucleated BM cells). Although it was necessary to continue to supplement these cultures with 5% fetal calf serum (FCS), the inclusion of the aforementioned BSA preparations provided enhanced PFC production for all lots of FCS tested. Similarly, these preparations of BSA made it feasible to also culture BM in autologous mouse sera (MS) or in medium without 2-mercaptoethanol (2-ME) if in the latter case the D-BSA was pretreated with 2-ME. Thus, the inclusion of GF-BSA or D-BSA in short term cultures of BM not only substantially increased the number of Ig-secreting B cells produced in response to TNP-LPS but seemed to eliminate the need to screen for supportive batches of FCS or MS. These preparations of BSA also facilitated hapten specific PFC responses of fetal liver cultures.