PPARγ expression is increased in systemic lupus erythematosus patients and represses CD40/CD40L signaling pathway.

Systemic lupus erythematosus (SLE) is a heterogeneous disease involving several immune cell types and pro-inflammatory signals, including the one triggered by binding of CD40L to the receptor CD40. Peroxisome-proliferator activated receptor gamma (PPARγ) is a transcription factor with anti-inflammatory properties. Here we investigated whether CD40 and PPARγ could exert opposite effects in the immune response and the possible implications for SLE. Increased PPARγ mRNA levels were detected by real-time PCR in patients with active SLE, compared to patients with inactive SLE PPARγ/GAPDH mRNA = 2.21 ± 0.49 vs. 0.57 ± 0.14, respectively (p < 0.05) or patients with infectious diseases and healthy subjects (p < 0.05). This finding was independent of the corticosteroid therapy. We further explored these observations in human THP1 and in SLE patient-derived macrophages, where activation of CD40 by CD40L promoted augmented PPARγ gene transcription compared to non-stimulated cells (PPARγ/GAPDH mRNA = 1.14 ± 0.38 vs. 0.14 ± 0.01, respectively; p < 0.05). This phenomenon occurred specifically upon CD40 activation, since lipopolysaccharide treatment did not induce a similar response. In addition, increased activity of PPARγ was also detected after CD40 activation, since higher PPARγ-dependent transcription of CD36 transcription was observed. Furthermore, CD40L-stimulated transcription of CD80 gene was elevated in cells treated with PPARγ-specific small interfering RNA (small interfering RNA, siRNA) compared to cells treated with CD40L alone (CD80/GAPDH mRNA = 0.11 ± 0.04 vs. 0.05 ± 0.02, respectively; p < 0.05), suggesting a regulatory role for PPARγ on the CD40/CD40L pathway. Altogether, our findings outline a novel mechanism through which PPARγ regulates the inflammatory signal initiated by activation of CD40, with important implications for the understanding of immunological mechanisms underlying SLE and the development of new treatment strategies.

Study of irradiated bothropstoxin-1 with60Co gamma rays: immune system behavior

Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.

Estudo de parasitos em colônias de ratos e de camundongos em biotérios brasileiros mantidos sob diferentes condiçöes de barreiras sanitárias / Parasite survery in mouse and rat colonies of Brazilian laboratory animal houses kept under differents sanitary barrier conditions

Um estudo parasitológico foi realizado para verificar as condiçöes de saúde de 15 colônias de camundongos e 10 colônias de ratos produzidos em 18 biotérios de instituiçöes brasileiras que fornecem animais para ensino, pesquisa e produçäo de imunobiológicos de uso médico ou veterinário. Métodos parasitológicos foram utilizados para diagnóstico de ácaros, piolhos, helmintos e protozoários parasitos. Um questionário foi respondido pelas instituiçöes com o intuito de obter informaçöes sobre a existência de barreiras contra infecçöes e programa de fiscalizaçäo sanitária de suas colônias. Os dados do questionário mostram que a maioria dos biotérios analisados näo possui um sistema de barreiras sanitárias eficiente capaz de manter animais sob condiçöes sanitárias controladas. Infecçöes por ecto e endoparasitos säo generalizadas nas colônias e a associaçäo de infecçöes múltiplas foi comum na maioria dos animais dos biotérios analisados. A prevalência dos parasitos detectados entre as colônias de camundongos e de ratos investigados foi: Myocoptes musculinus (46,6 por cento), Myobia musculi (26,6 por cento), Radfordia ensifera (13,3 por cento), Syphacia obvelata (86,6 por cento). Aspiculuris tetraptera (60,0 por cento), Hymenolepis nana (53,3 por cento), Spironucleus muris (80,0 por cento), Tritrichomonas muris (80,0 por cento), Giardia muris (66,0 por cento), Entamoeba muris (20,0 por cento), Eimeria sp. (13,3 por cento), Hexamastix muris (26,6 por cento), Poliplax spinulosa (30,0 por cento), Poliplax serrata (10,0 por cento), Radfordia ensifera (30,0 por cento), Syphacia muris (80,0 por cento), Hymenolepis nana (40,0 por cento), Trichosomoides crassicauda (55,5 por cento), Spironucleus muris (90,0 por cento), Tritrichomonas muris (80,0 por cento), Giardia muris (60,0 por cento), Entamoeba muris (80,0 por cento), Eimeria sp. (60,0 por cento) e Hexamastix muris (60,0 por cento)