Colibacillosis: immunopathology and immunoprophylaxis of diarrheal diseases in pigs
Main researcher
: VALPOTIĆ, IVICA (66266) Assistants
GRABAREVIĆ, ŽELJKO (14604)
TOMAŠKOVIĆ, MARIJA (92334)
ĆURIĆ, STIPICA (108013)
GERENČER, MARIJAN (58892)
MARINCULIĆ, ALBERT (139934)
LACKOVIĆ-VENTURIN, GORDANA (105166)
GREGORKO, VESNA (80793)
JERČIĆ, JURE (18592)
ŽUBČIĆ, DAMIR (191460)
TRUTIN-OSTOVIĆ, KARMEN (142676)
HUZJAK, DRAŽEN (161071)
ŠVER, LIDIJA (900613)
Type of research: applied Duration from: 01/01/91. to 12/31/95. Papers on project (total): 64
Papers on project quoted in Current Contents: 16
Institution name: Veterinarski fakultet, Zagreb (53) Department/Institute: Department of Biology Veterinary Faculty University of Zagreb Address: Heinzelova 55 City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (01)2390-144
Fax: 385 (01)214-697
E-mail: 161.53.93.3.valpotic
Summary: Postweaning colibacillosis is an economically significant
disease in swine for which no effective vaccine is available. Porcine F4
(K88)+ enterotoxigenic Escherichia coli (ETEC) strains are recognized as a
major cause of diarrheal disease in suckling and weaned pigs. It is assumed
that the harmful effects of ETEC are due entirely to enterotoxins and that
nontoxigenic (non-ETEC) fimbriated strains of E. coli should be effective
and safe oral vaccines. Much of the work of caracterizing porcine
intestinal mucosal immune system and developing oral vaccines has focused
on the humoral immunity against F4 (K88)+ enterotoxigenic Escherichia coli
(ETEC) strains. The current research will investigate the harmful effects
and immunogenicity of genetically-engineered non-toxigenic E. coli strains
containing wild-type or recombinant plasmids encoding F4 antigen to
establish the role of the fimbrial antigen in 1) causing diarrhea and
mucosal damage, 2) inducing an inflammatory response of gut-associated
lymphoid tissue (GALT), and 3) stimulating the protective immune response
at the mucosal surfaces mediated by the cellular elements of GALT. Non-ETEC
strain 2407 expressing F4ac fimbrial antigen induced only a mild mucosal
damage and was able to invoke moderate leukocyte infiltration in
jejunum/ileum. Among T lymphocytes an increase of CD8a+, CD4a+, or
SWC1a+/CD8a+ cells in lamina propria (LP), Peyer's patches (PP) and
mesenteric lymph node (MLN), respectively, was observed. Both non-ETEC
strains (1466 and 2407) activated lymphocytes from PP and MLN to respond
better to common mitogens, F4ac antigen or immonologic response modifiers
(IRMs). The results indicate that F4ac+ non-ETEC strain 2407 seems to be
the best source of protective antigen in developing of safe and effective
live oral vaccine against postweaning colibacillosis. However, before any
firm conclusions (and field trial), it is necessary to study the vaccinal
antigen using 1) F4 receptor-positive (susceptible) and -negative
(resistant) pigs, and 2) IRMs (peptidoglycan monomer and Baypamun) applied
in vivo along with non-ETEC strain 2407.
Research goals: The basic hypothesis of the project assumes that F4
antigen of enterotoxigenic E. coli (ETEC) strain, and also of non-ETEC
strains, could induce besides well known local humoral immune response
(secretory IgA), less studied cellular immune response of porcine
gut-associated lymphoid tissues (GALT). The later response should be
exhibited through enhanced infiltration and reactivity (proliferation) of
lymphoid cells in small mesenteric lymph nodes (MLN) of weaned pigs. From
this hypothesis three main questions arose: (1) whether or not F4+ non-ETEC
strains (authentic or recombinant) are able to invoke an equally strong
cellular immune response in the GALT as F4+ ETEC strain does, without
causing damage in the small intestinal mucosa of experimentally infected
pigs, (2) is it possible to enhance nonspecifically the intestinal
protective immunity, that was established (after ETEC/non-ETEC
inoculation), by means of immune response modifiers (IRM), and (3) would it
be practically feasible that orally applied allogeneic immunoglobulins (Ig)
or fimbrial vaccine can protect pigs from naturally or artificially induced
diarrheal disease due to E. coli infections. These questions should be
answered through the following objectives of the research: - determine
frequency and significance of intestinal F4 receptor for adhesion of F4+
ETEC strains in pigs and develop the practical test for identification of
genetically resistant (receptor-negative) swine; - test the protective
ability of fimbrial vaccine Colimix in specific, and allogeneic Ig in
nonspecific immunoprophylaxes of diarrheal disease caused by F4+ ETEC
strains in genetically susceptible and resistant pigs; - determine the
quantitative proportions and demonstrate in situ distribution of T
lymphocyte subsets (SWC1+, CD2+, CD4+, CD8+ cells) in LP, PP and MLN of
pigs inoculated with F4+ ETEC or non-ETEC strains; - assess the functional
properties of T and B lymphocytes from the GALT in in vitro stimulation
tests using common mitogens, F4 antigen, or IRM after in vivo activation
with F4 fimbrial and/or enterotoxin antigens; - determine the extent and
intensity of mucosal lesions in the small intestine (at microscopic and
ultrastructural levels) of experimentally infected pigs. The results
obtained on the basis of these objectives would contribute to our
understanding of a role and effectiveness of local (intestinal) cellular
immune mechanisms in the GALT against bacterial infection, and enable
development of a safe (without toxins) and effective (with F4 immunogen)
live oral vaccine against colibacillosis caused by F4+ ETEC strains in
postweaning pigs.
COOPERATION - PROJECTS
Name of project
: 3-03-301 Trihineloza: Imunologija i
imunopatologija zoonoze Name of institution: Zavod za parazitologiju i invazijske bolesti,
Veterinarski fakultet, Sveučilišta u Zagrebu City: 10000 - Zagreb, Croatia
Name of project
: 3-03-315 Kontrola dominantnih bakterijskih
infekcija svinja Name of institution: Veterinarski institut, Zagreb City: 10000 - Zagreb, Croatia
Name of project
: 3-03-299 Utjecaj paragenetskih faktora na
patologiju u svinja Name of institution: Zavod za patologiju i patološku morfologiju,
Veterinarski fakultet, Sveučilišta u Zagrebu City: 10000 - Zagreb, Croatia
Name of project
: 3-03-340 Mikroklima i etologija u svinjogojskoj
proizvodnji Name of institution: Zavod za zoohigijenu, Veterinarski fakultet,
Sveučilišta u Zagrebu City: 10000 - Zagreb, Croatia
Name of project
: FG-CRO(YU) 933 Monitoring of swine pathology II Name of institution: Zavod za patologiju i patološku morfologiju,
Veterinarski fakultet, Sveučilišta u Zagrebu City: 10000 - Zagreb, Croatia
Name of project
: 1-08-303 Tumori i metastaze : Biologija i
liječenje Name of institution: Zavod za animalnu fiziologiju
Prirodoslovno-matematičkog fakulteta, Sveučilišta u Zagrebu City: 10000 - Zagreb, Croatia
COOPERATION - INSTITUTIONS
Name of institution
: National Animal Disease Center, Ames, Iowa,
SAD, US Department of Agriculture, Agricultural Research Service Type of institution: State institute Type of cooperation: Joint project City: 50010 IA - Ames, SAD
Name of institution
: Veterinary Institute of Hungarian Academy
of Sciences, Budimpešta, Mađarska Type of institution: State institute Type of cooperation: Occasional exchange of information City: HA-1581 - Budapest, Mađarska
Name of institution
: University of Bristol, Veterinary Faculty Type of institution: University/Faculty Type of cooperation: Joint project City: Bristol, Velika Britanija Other information about the project.