Biomedical subjects

F Bolas-Fernandez

Publications and source records attributed to F Bolas-Fernandez.

13 recordsLinked to original sources

PubMed2006

Microcapsules formulated in the enteric coating copolymer Eudragit L100 as delivery systems for oral vaccination against infections by gastrointestinal nematode parasites.

Microcapsules using the copolymer of methacrylic acid (Eudragit L100) were formulated for oral delivery of vaccines against the enteral/parenteral nematode parasite Trichinella spiralis. Antigenic preparations from first stage larvae (L1) of T. spiralis were microencapsulated in Eudragit L100. The microcapsules prepared by the spray drying method were resistant to acid pH, although the antigen was rapidly released under neutral and basic environmental conditions. The native protein conformation and biological activity was preserved in the microcapsules, as assessed by SDS-PAGE and ELISA. When administered to NIH mice, the antigen loaded microcapsules protected against infection by T. spiralis at both the intestinal and muscular levels, the worm burden diminishing by 45.58 and 53.33%, respectively. Furthermore, following administration of the microparticles an increase of the serum IgG1 response, a marker for the Th2 type response, was evident. These results indicate that microcapsules formulated with anionic biocompatible polymers such as Eudragit may be useful for oral vaccination against nematode infections.

Administration, Oral↗

PubMed2000

Comparison of IgG3 responses to carbohydrates following mouse infection or immunization with six species of Trichinella.

The IgG3 antibody responses to carbohydrate epitopes were compared in BALB/c mice infected or immunized with six species of Trichinella: T. spiralis (T1), T. nativa (T2), T. britovi (T3), T6, T. nelsoni (T7), and T8. The dynamics of IgG3 responses and antigen recognition following infection or immunization were measured by ELISA and Western blot respectively, using glycosylated and deglycosylated larval crude extracts (LCE) prepared from homologous isolates. A high degree of protein glycosylation was found in all species and with similar profiles. Deglycosylation was completely achieved only in LCE from T1 and T6 isolates. The dynamics of IgG3 responses following infection or immunization significantly differed whereas the antigen recognition profiles appeared similar. Variations in the levels and antigen recognition patterns of IgG3 among the different species were apparent. The highest IgG3 levels were recorded in infections by the T8 isolate and the lowest in infections by the T6 isolate, whereas for immunization the highest IgG3 response was induced by T7 and the lowest by T8. Following antigen deglycosylation, the IgG3 responses were significantly reduced or abrogated and the recognition patterns markedly modified or suppressed in the different species of Trichinella.

Animals↗

PubMed1997

Immunization of mice against Trichinella spiralis and T. britovi using excretory and secretory antigens.

Immune responses to immunization and infection with Trichinella spiralis and T. britovi were studied in NIH high-responder mice. Overall it was shown that T. britovi was the more immunogenic, immunization and challenge with this species giving greater host-protective immunity. This greater immunogenicity was reflected in higher proliferative responses when mesenteric node lymphocytes (MLNC) from immunized mice were restimulated with T. britovi antigens in vitro and in higher levels of T helper 2 (Th2) lymphocyte-dependent specific IgG1 antibody responses against this species. MLNC from mice immunized against T. britovi released more IL-5 when restimulated in vitro, again suggesting a greater T helper 2 subset response, but after infection the highest levels of IL-5 were recorded from MLNC taken from T. spiralis challenged mice. These data are discussed in relation to current understanding of immunological differences between species and isolates of the genus Trichinella.

Animals↗

PubMed1993

Dynamics of porcine humoral responses to experimental infections by Spanish Trichinella isolates: comparison of three larval antigens in ELISA.

Five groups of six helminth-free pigs of the Iberian and Landrace x White breeds were each experimentally-infected randomly at a dose of 150 larvae per kg, body weight with one of the five Trichinella isolates, coded as Gm-1, Co-77, Laso, C-76 and Mad-83. These isolates were selected from the two Trichinella species (T. spiralis and T. britovi) so far identified in the Iberian Peninsula. Specific antibodies against the infections were measured on days -14, 0, 6, 16, 20, 27, 34, 49, 63 and 82 post-infection (p.i.), in a comparative indirect ELISA assay using three different antigens prepared from the muscle stage of the parasite. The antigens were a crude saline larval extract (CSLE), excretory-secretory (ES) and surface stripped cetyl-trimethyl ammonium bromide detergent (CTAB) products. Over all, the dynamics of antibody responses were very similar for infections with the five different isolates, although a significant delay in positive and maximum antibody titres was seen in the group infected with C-76, the isolate exhibiting a marked low infectivity to domestic mammals. ELISA with the crude antigen was more sensitive (positive antibody titres appeared between days 6 and 16 p.i.) than with the ES and CTAB preparations (positive titres appeared between days 16 and 20 p.i.). For infections with the C-76 isolate, positive titres appeared between days 16 and 20 p.i. with the CSLE antigen and, on day 27 p.i. with the ES and CTAB antigens. Little cross-reactivity with other common porcine helminth infections appeared only when ELISA was carried out with CSLE and CTAB antigens.

Animals↗

PubMed1992

Immunization against geographical isolates of Trichinella spiralis in mice.

Partially purified antigen preparations from six isolates of Trichinella spiralis were used to immunize mice. Immunogenicity of the antigens was assessed in terms of antibody and lymphocyte responses and ability to stimulate protective immunity against challenge. Isolate antigens showed considerable cross-reactivity, and all elicited protective responses. Two major patterns of immunizing ability could be distinguished: (a) isolates that immunized well against heterologous challenge and elicited good immunity in London isolate-immunized mice (C-76 and Laso), and (b) isolates that immunized poorly against heterologous challenge and were least effective in London isolate-immunized mice (GM-1 and Mad-83). The immunogenicity of one isolate (C-76) was markedly greater than the others, inducing rapid loss in unvaccinated mice, almost complete protection in London isolate-immunized mice, and immunity in London isolate-challenged mice equivalent to the homologous antigen. These variations in immunogenicity, cross-reactivity and immunizing ability are discussed in terms of constraints that may operate against the development and use of vaccines against parasites that are widely distributed geographically.

Animals↗

PubMed1991

DNA polymorphisms within Spanish Trichinella isolates.

A total of 13 Spanish Trichinella isolates were characterised by DNA analysis. Genomic DNA cross-hybridisation tests revealed two distinct groups that exhibited weak cross-reactions. Further diagnostic subdivision was attempted according to restriction-fragment polymorphism using a cloned T. spiralis DNA repetitive fragment as a probe, but no major difference between the two Trichinella groups was observed.

Animals↗

PubMed1990

Infectivity, antigenicity and host responses to isolates of the genus Trichinella.

Comparisons were made of the infectivity and antigenicity of 4 Trichinella spiralis isolates (S, D, Y, W), of quite different geographical origins, and T. pseudospiralis (P) in rapid- and slow-responder inbred mice. Infectivity was measured by the Index of Reproductive Capacity (ICR) expressed as the ratio between the number of muscle larvae recovered on day 30 post-infection (p.i.) and the numbers of larvae given at infection. Antigen recognition was measured by the degree of proliferation of mesenteric lymph node cells (MLNC) to in vitro stimulation with crude muscle larvae antigen (CMLA) and by the total antibody responses to CMLA at day 25 p.i. as measured by ELISA. Regarding infectivity the isolates fell into two groups, high infectivity (S, D and Y) and low infectivity (W and P). Analysis of CMLA, detergent-stripped (CTAB) and 125I-labelled surface larval proteins was made by SDS-PAGE under reducing conditions. Differences in antigen profiles were seen in all antigen preparations, being most noticeable in CTAB and 125I-labelled proteins from W and P isolates. Antigen recognition by polyclonal infection-derived antisera and by monoclonal antibodies raised against the T. spiralis London strain (L) was studied in the W (Arctic) and S (Spanish) isolates. Polyclonal antisera recognized different antigens in the S and W isolates, as did the monoclonal antibody, although recognition was more restricted. Neither antibody recognized a 64 kDa band in the W isolate which was clearly visible in the others tested.

Animals↗

PubMed1989

Infectivity of Trichinella isolates in mice is determined by host immune responsiveness.

A comparison was made of the development, survival and reproduction of 5 isolates of Trichinella spiralis in inbred mice. Low responder C57BL/10 mice allowed worms of all isolates to survive longer and reproduce more successfully than did high responder NIH mice, suggesting that host immunity exerted a dominant influence upon infectivity. One isolate (Is-5 (W) -an arctic isolate) had a markedly lower infectivity than all other isolates, and was selected for more detailed study, together with isolate Is-1 (S) (a temperate isolate) which showed high infectivity. The lower infectivity of Is-5 (W) reflected a more rapid onset of immunity in mice infected with this parasite, immunity reducing the reproductive potential of female worms and causing an early expulsion from the intestine. No evidence of a dose-dependent suppression of immunity was found to explain the higher infectivity of Is-1 (S). Is-5 (W) provided a very rapid mucosal mastocytosis Is-1 (S) elicited higher levels of circulating parasite-specific antibodies than did Is-5 (W). These results are discussed in relation to the interplay of parasite immunogenicity and host immune responsiveness in determining infectivity, and point to the importance of identifying those immunodominant parasite molecules which control the balance of the host-parasite relationship.

Animals↗

PubMed1988