Parasitaemia levels in Plasmodium chabaudi infected-mice modify IFN-gamma and IL-10 expression after a homologous or heterologous challenge.

CB6F1 mice infected with the nonlethal Plasmodium chabaudi chabaudi AS suffer parasitaemia levels up to 40% (full parasitaemia, FP) and develop both homologous and heterologous (against the lethal Plasmodium yoelii 17XL) protective immunity. However, if mice are treated with anti-malarial drug when parasitaemia is below 10% (low parasitaemia, LP), they only develop homologous immunity. For the better understanding of this interesting dissociation related to the degree of parasitaemia, in this work, we studied the genetic expression of some cytokines.

Quantification of cytokine gene expression using an economical real-time polymerase chain reaction method based on SYBR Green I.

Assessment of cytokine expression has become crucial to understand host responses to infections as well as autoimmunity. Several approaches including Northern blot, RNase protection assay and enzyme-linked immunosorbent assay have been used for this purpose, but they are time consuming, labour intense, and relatively large quantity of the samples is usually required. Recently, a technique termed real-time reverse transcriptase-polymerase chain reaction (RT-PCR) has been developed to determine genetic expression with great sensitivity and specificity; however, specialized instrumentation and costly reagents are usually needed.

Apoptosis in lymph nodes and changes in lymphocyte subpopulations in peripheral blood of pigs infected with porcine rubulavirus.

In a first experiment, five pigs were inoculated intranasally with porcine rubulavirus (PoRV) at 5 days of age and killed 7 days post-infection (pi). In a second experiment, four pigs were infected with the same virus at 17 days of age and killed at 9 or 15 days pi. Control piglets in each experiment received uninfected cell culture supernate.

Mouse splenic CD4+ and CD8+ T cells undergo extensive apoptosis during a Plasmodium chabaudi chabaudi AS infection.

The presence and phenotype of apoptotic lymphocytes was studied in spleen cell suspensions taken from CB6F1 mice infected with Plasmodium chabaudi chabaudi AS. High levels of apoptotic cells were found, associated with high parasitaemias and splenomegaly. This was also accompanied by expansion and disarray of spleen white pulp.

Plasmodium chabaudi chabaudi: effect of low parasitemias on immunity in CB6F1 mice.

We examined the effect that low parasitemias have on the immune response of CB6F1 mice infected with Plasmodium chabaudi chabaudi AS. Ascending parasitemias were stopped by chloroquine treatment when they were between 1.6 and 9.

IgG antibody subclasses, tumor necrosis factor and IFN-gamma levels in patients with type II lepra reaction on thalidomide treatment.

A group of 9 Mexican lepromatous leprosy patients was studied at the beginning of a type II reaction (erythema nodosum leprosum, ENL) and after 1 or 2 months of thalidomide treatment. ENL patients at the onset of the reaction had slightly higher amounts of anti-Mycobacterium leprae IgG1 and IgG2 antibodies, compared to similar lepromatous patients that did not develop ENL. Neither these antibody levels nor IgM and the other IgG subclasses were importantly modified after thalidomide treatment.

The spleen, IgG antibody subsets and immunity to Plasmodium berghei in rats.

The development of IgG subclass-specific antibody responses to Plasmodium berghei in spleen-chimeric rats were monitored to determine if there was any relationship between IgG subset profiles and resistance. Strongly immune eusplenic rats respond to challenge with P. berghei by producing high levels of parasite-specific IgG2a, IgG2b and IgG2c but only modest levels of IgG1.

Seroepidemiological studies of cutaneous leishmaniasis in the Campeche state of México.

Seroepidemiological studies of cutaneous leishmaniasis were carried out in 169 individuals in a rural area of the Campeche state of México. Fifty showed cutaneous lesions suggestive of leishmaniasis, 70% were parasite positive and 96% skin test positive. An overall 40% positivity to skin test with Montenegro's antigen was found.

Thalidomide and its metabolites have no effect on human lymphocyte proliferation.

Thalidomide is a drug that is being used in several diseases with an immunological component, but the effects on the different immune functions have only been studied partially. Therefore, we studied the effect of thalidomide on PPD-or Con-A-induced proliferation of human mononuclear cells. We found no direct effect of thalidomide at up to 50 micrograms/ml on the cultures.

Protection of rats against malaria by a transplanted immune spleen.

A number of reports have suggested that the spleen plays a key role in the regulation of immunity to malaria but the role, if any, of other tissues is less clear. Furthermore, numerous functional changes occur in the spleen following malaria infection and it is not known whether the spleen's role relates primarily to its content of malaria-specific lymphocytes or to the altered structure and function that has occurred. To address these issues we have generated splenic chimeras by transplanting spleens between Plasmodium berghei-immune and naive rats.

Antibody formation in the transplanted spleen: a simple method of splenic transplantation in the rat using the cuff technique.

To study whether transplanted spleens produce antibodies or not, a simplified model of spleen transplantation using the cuff technique was developed. The whole spleen with vascular pedicles was implanted in the syngeneic DA (RT1a) rat combination, using the cuff technique applied to the renal artery and vein of the recipient. The functions of the grafted spleen were tested by antibody formation-titers of antibody in the serum and plaque-forming cells in the graft spleen against xenogeneic [BALB/c (H-2d) mouse] antigen.

Infection of BALB/c, C57B1/6 mice and F1 hybrid CB6F1 mice with strains of Leishmania mexicana isolated from Mexican patients with localized or diffuse cutaneous leishmaniasis.

Mice from the syngeneic strains BALB/c, C57B1/6 and (BALB/cxC57B1/6)F1 hybrids (CB6F1) were infected in the footpad with six different strains of Leishmania mexicana mexicana isolated from Mexican patients. Three Leishmania strains were isolated from patients with localized cutaneous leishmaniasis (LCL, the benign form of the disease) and three from patients with diffuse cutaneous leishmaniasis (DCL, the malignant form of the disease). In BALB/c mice, four Leishmania strains showed a sustained fast growth from 4 to 5 weeks postinfection until the end of the experiment (15 weeks), and the other two grew slowly up to 10 or 12 weeks after infection and then started to grow faster.

Anti-Thy-1 treated and irradiated spleen cells from (BALB/c x C57Bl/6) F1 mice infected with Plasmodium chabaudi chabaudi can transfer protection into irradiated hosts.

The transfer of spleen cells from (BALB/c x C57Bl/6) F1 mice recovered from a Plasmodium chabaudi chabaudi AS infection into irradiated syngeneic recipients conferred protection. Neither elimination of Thy-1+ cells nor in vitro irradiation of immune cells before transfer affected protection while both anti-Thy-1 treatment and irradiation abolished the appearance of anti-P. c.

Human leukocyte migration inhibition factor (LIF) increases polymorphonuclear cell endocytosis.

We prepared supernatants of Concanavalin-A activated human lymphocytes containing high titers of leukocyte migration inhibition factor (LIF). A pool of these supernatants was filtered thorough sephadex 6-100 as well as a pool of supernatants from parallel non activated cultures. A migration assay was carried out for each activated fraction, using as control migration the same fraction from non activated supernatants.

The adoptive transfer of T-cell dependent immunity to Plasmodium chabaudi chabaudi in CBA/Ca mice is achieved only after superinfection of immune spleen cell donors.

The transfer of spleen cells from CBA/Ca mice recovered from a P. c. chabaudi AS primary infection into irradiated syngeneic recipients conferred very poor protection.

Production of leukocyte migration inhibition factor (LIF) and migration stimulation factor (MStF) by CD4+ and CD8+ human lymphocytes subsets and T-cell clones.

The production of the lymphokines leukocyte migration inhibition factor (LIF) and migration stimulation factor (MStF) at the level of CD4+ and CD8+ human lymphocyte subsets was investigated. In a first series of experiments, anti-CD4 and anti-CD8 monoclonal antibodies capable of inhibiting the activation by concanavalin-A (Con-A) of the respective T-cell subset were used. It was observed that when CD8+ cell activation was blocked, LIF was always produced after Con-A activation.

Modulation of Thy-1 alloantibody responses: donor cell-associated H-2 inhibition and augmentation without recipient Ir gene control.

In this study we have found that in vivo PFC responses to Thy-1 are strongly modulated by H-2 gene products in at least 2 ways. First, a profound inhibition of primary PFC responses occurs when foreign H-2 antigens are expressed on Thy-1 incompatible donor cells. This interference effect does not reflect a requirement for H-2-restricted antigen presentation by donor cells, since it is also seen using semi-syngeneic antigenic cells that share a full H-2 haplotype with the recipient.