DTIC ADA471839: Superantigen-Induced Cytokine Release from Whole-Blood Cell Culture as a Functional Measure of Drug Efficacy after Oral Dosing in Nonhuman Primates

0.29 MB·English

by  Defense Technical Information Center

ResearchinVeterinaryScience83(2007)182–187
www.elsevier.com/locate/rvsc
Superantigen-induced cytokine release from whole-blood cell culture
as a functional measure of drug efficacy after oral dosing in
nonhuman primates
Teresa Krakauer a,*, Julie Stephens b, Marilyn Buckley a, Mallory Tate c
aIntegratedToxicologyDivision,UnitedStatesArmyMedicalResearchInstituteofInfectiousDiseases,FortDetrick,Frederick,MD21702-5011,USA
bVetMedDivision,UnitedStatesArmyMedicalResearchInstituteofInfectiousDiseases,FortDetrick,Frederick,MD21702-5011,USA
cAnimalResourcesBranch,ScientificResourcesProgram,CentersforDiseaseControlandPrevention,Atlanta,GA30333,USA
Accepted9December2006
Abstract
EvaluationofdrugefficacyforhumandiseasesisroutinelyperformedinanimalmodelsforefficiencyandinaccordancewithFDA
regulations.Rhesusmacaqueshavebeenusedasmodelsforvariouslethaldiseasesandcorrelatesofimmunity,asnonhumanprimates
(NHP)closelyresemblehumans.Weexaminedtheexvivocytokineresponseofsuperantigen-stimulatedwhole-bloodcellsasafirststep
totherapeuticefficacytestingforbacterialsuperantigen-inducedshockinNHPafteroraldosingofpentoxifylline.Dosesof120mg/kgof
pentoxifylline effectively attenuated staphylococcal enterotoxin B-induced tumor necrosis factor a (TNFa), gamma interferon (IFNc)
and interleukin 2 (IL-2) in ex vivo culture of NHP whole-blood cells by 88%, 81%, and 76%, respectively, whereas lower doses of 48
or72mg/kg hadno inhibitory effect. Thus cytokine release of stimulated peripheral blood cellsprovides a convenient biological mea-
surementof the anti-inflammatory potency of pentoxifylline and hasthe advantageof assessing functionalresponses to a specificbio-
toxin of interest.
PublishedbyElsevier Ltd.
Keywords: Pentoxifylline;Cytokines;Whole-bloodcellculture
1. Introduction productionofproinflammatorycytokinesandTcellprolif-
eration,causingclinicalsymptomsthatincludefever,hypo-
Staphylococcal enterotoxin B (SEB) and related super- tension,andshock(Kotzinetal.,1993;Fraseretal.,2000).
antigenictoxinsarepotentactivatorsoftheimmunesystem At present, there is no known treatment for staphylo-
and cause a variety of human diseases, ranging from food coccal exotoxins (SE)-induced shock except for the use of
poisoning to toxic shock (Kotzin et al., 1993; Fraser etal., intravenous immunoglobulins (Darenberg et al., 2004).
2000; McCormick et al., 2001; Baker and Acharya, 2003; Various strategies have been devised to treat SE-induced
Proft and Fraser, 2003). These toxins bind to both MHC diseases including blocking SE binding to host cells via
class II molecules and specific Vb regions of T cell recep- interactionwithMHC class IImolecules orT cellreceptor
tors (Choi et al., 1989; Mollick et al., 1991), resulting in (Krakauer, 1999; Visvanathan et al., 2001; Geller-Hong
theactivationofbothmonocytes/macrophagesandTlym- andGupta,2003;Rajagopalanetal.,2004).Weandothers
phocytes (Krakauer, 1999; Proft and Fraser, 2003). The previously showed that induction of the proinflammatory
interactionsofthesetoxinswithhostcellsleadtoexcessive cytokines and the signaling pathways used by SE are
important targets as excessive proinflammatory cytokines
mediate the toxic effects of SE (Parsonnet, 1989; Trede
* Correspondingauthor.Tel.:[phone];fax:[phone].
E-mailaddress:[email protected](T.Krakauer). et al., 1991; Miethke et al., 1993; Stiles et al., 1993;
0034-5288/$-seefrontmatter PublishedbyElsevierLtd.
doi:10.1016/j.rvsc.2006.12.004
Report Documentation Page Form Approved
OMB No. 0704-0188
Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,
including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington
VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it

does not display a currently valid OMB control number.
1. REPORT DATE 2. REPORT TYPE 3. DATES COVERED
1 OCT 2007 N/A -
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Superantigen-induced cytokine release from whole-blood cell culture as a
5b. GRANT NUMBER
functional measure of drug efficacy after oral dosing in nonhuman
primates. Research in Veterinary Science 83:182-187 5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
Krakauer, T Stephens, J Buckley, M Tate, M
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
United States Army Medical Research Institute of Infectious Diseases, REPORT NUMBER
TR-07-044
Fort Detrick, MD
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)
11. SPONSOR/MONITOR’S REPORT
NUMBER(S)
12. DISTRIBUTION/AVAILABILITY STATEMENT
Approved for public release, distribution unlimited
13. SUPPLEMENTARY NOTES
14. ABSTRACT
Evaluation of drug efficacy for human diseases is routinely performed in animal models for efficiency and
in accordance with FDA regulations. Rhesus macaques have been used as models for various lethal diseases
and correlates of immunity, as nonhuman primates (NHP) closely resemble humans. We examined the ex
vivo cytokine response of superantigen-stimulated whole-blood cells as a first step to therapeutic efficacy
testing for bacterial superantigen-induced shock in NHP after oral dosing of pentoxifylline. Doses of
120mg/kg of pentoxifylline effectively attenuated staphylococcal enterotoxin B-induced tumor necrosis
factor alpha (TNFalpha), gamma interferon (IFNgamma) and interleukin 2 (IL-2) in ex vivo culture of
NHP whole-blood cells by 88%, 81%, and 76%, respectively, whereas lower doses of 48 or 72mg/kg had no
inhibitory effect. Thus cytokine release of stimulated peripheral blood cells provides a convenient
biological measurement of the anti-inflammatory potency of pentoxifylline and has the advantage of
assessing functional responses to a specific biotoxin of interest.
15. SUBJECT TERMS
pentoxifylline, cytokines, whole-blood culture, drug efficacy, superantigen, laboratory animals, nonhuman
primates
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF
ABSTRACT OF PAGES RESPONSIBLE PERSON

a. REPORT b. ABSTRACT c. THIS PAGE SAR 6
unclassified unclassified unclassified
Standard Form 298 (Rev. 8-98)
Prescribed by ANSI Std Z39-18
T.Krakaueretal./ResearchinVeterinaryScience83(2007)182–187 183
Krakauer, 2005). TNFa and IFNc are key mediators in nosorbent assay to be free of antibodies to SEB were used
SEB-induced toxic shock, and in vivo studies also show a in this study. The absence of anti-SEB antibodies in these
correlation between increased serum levels of these cyto- monkeys provide assurance that results from this study
kines with SEB-induced lethality (Miethke et al., 1992; wouldnotbeduetoantibodyneutralizationorotherinter-
Stiles et al., 1993). Genetic knockout mice deficient in ference.Monkeysweremaintainedinindividualcageswith
TNF receptor type 1 (TNFR1) or IFNc receptor are also full access to filtered tap water, and were fed commercial
resistant to SEB-induced shock (Stiles et al., 1999). Neu- monkey chow, supplemented with fresh fruits. Research
tralizing antibodies against TNFa prevented SEB-induced was conducted in compliance with the Animal Welfare
lethality (Miethke et al., 1992). Murine models are used Act and other federal statutes and regulations. All experi-
mostoftenintherapeuticefficacystudiesbecauseimmuno- ments involving animals adhered to principles stated in
logical reagents are available and testing can be done the Guide for Care and Use of Laboratory Animals,
quickly and economically, especially when lethality is used National Research Council, 1996. All animal manipula-
asan endpoint (Krakauerand Stiles, 2006). However, spe- tions were performed under an anesthetic dose (3–6mg/
cies differences indicate mouse models often do not mimic kg intramuscularly) of Telazol(cid:2) (tiletamine hydrochloride
human diseases and nonhuman primates (NHP) are often and zolazepam hydrochloride).
used as human surrogates. In particular, in vivo studies
with SE using mouse models require potentiating agents 2.3. Pentoxifylline doses and regimens
toenhancethetoxiceffectsofSE(Stilesetal.,1993;Blank
et al., 1997) because mice are less sensitive to SE due to HealthyNHP(n=4)receivedpentoxifylline(startingat
lower affinity of SE to mouse MHC class II molecules 48mg/kg every 8h) via orogastric tube every 8h. Pentox-
(Mollick et al., 1991). Rhesus macaques have been used ifylline was supplied as a 50mg/ml aqueous solution.
as a lethal model for inhaled SEB, as pathogenic features Sham-treated control animals (n=2) received water oro-
of SEB intoxicated monkeys resemble those of humans gastricly following exactly the same schedule as drug-trea-
(Hodovaletal.,1968).Therefore,NHPmayprovideacon- ted NHP. The dose of pentoxifylline was increased in a
sistent model for the development of therapeutics for SE- series of three subsequent experiments to 72mg/kg,
induced shock in humans. It is not known at present if 96mg/kg and 120mg/kg. Some NHP were reused after a
drugs effective in mouse models of SEB intoxication can resting period of at least 3months. Blood was taken from
be applied to NHP or human. monkeys immediately before the start of drug treatment
Pentoxifylline is a methylxanthine derivative that inhib- (time=0)and peripheralblood cellsfrom eachNHP were
its the production of TNFa by endotoxin- or SEB-stimu- established as a baseline for that particular animal. Blood
lated human peripheral blood mononuclear cells (Neuner wascollectedagain3hafterthefirstdoseofpentoxifylline
et al., 1994; Krakauer and Stiles, 1999) and is effective in andat27hafterthefirstdose,i.e.,3hafterthefourthdose
reducing serum cytokines in mice with SEB-mediated from each NHP. At every time point, blood cellswere cul-
shock (Krakauer and Stiles, 1999). The present study was tured within 30min after collection. No side effects were
undertaken to provide a first estimate for a therapeutic observedinNHPreceivingmultipledosesofpentoxifylline.
dose of pentoxifylline in attenuating superantigen-medi-
ated inflammatory mediators ex vivo in NHP after oral 2.4. Ex vivo whole-blood cell culture and cytokine assays
dosing. Additionally, we wanted to establish ex vivo cul-
ture conditions for NHP whole-blood cells as NHP repre- BloodwascollectedinEDTAtubesanddiluted1/5with
sent a realistic animal model for therapeutic development RPMI supplemented with 10% heat-inactivated fetal calf
against various human diseases. serum and plated in 24-well cell culture plates. Cells were
stimulated with a predefined optimal concentration of
2. Materials and methods 750ng/mlofSEBorSEAfor20hat37(cid:3)C.Theconcentra-
tion of superantigens is consistent with those previously
2.1. Reagents used in in vitro studies using human peripheral blood
mononuclearcells(Fraseretal.,1992;KrakauerandStiles,
SEBandSEAwereobtainedfromToxinTechnology(Sar- 1999). Supernatants were harvested and kept frozen until
asota, FL). The endotoxin content of these SEB and SEA assayed.LevelsofTNFa,IFNcandIL-2present insuper-
preparationswas<1ngofendotoxinpermgofSEB,asdeter- natantsweredeterminedbyELISAkits,accordingtoman-
minedbytheLimulusamoebocytelysategelationtest(Bio- ufacturer’s specifications (Biosource, Camarillo, CA).
whittaker, Frederick, MD). Pentoxifylline and other
commonreagentswereobtainedfromSigma(St.Louis,MO). 2.5. Statistical analysis
2.2. Animals CytokinedatafromindividualNHPareexpressedasthe
mean pg/ml±SE of duplicate samples. Inhibition of SE-
Twenty-four rhesus monkeys (Macaca mulatta), each stimulatedcytokinesbypentoxifyllineisexpressedasaper-
weighing 4–8kg, prescreened by an enzyme-linked immu- centage of SE-treated whole-blood cells obtained at zero
184 T.Krakaueretal./ResearchinVeterinaryScience83(2007)182–187
time before drug or sham treatment. Inhibition data were ers of activation because they are responsible for the
subsequently analyzed for significant differences by Stu- pathogenic effects of SE (Miethke et al., 1993; Stiles
dent’s t-test with Stata (Stata Corp., College Station, et al., 1993). The cell sources for these three prototypical
TX).TheresultswereconsideredsignificantifPwas<0.05. cytokinesexaminedalsodiffered.TNFaisproducedmostly
by activated monocytes and T cells, whereas T cells and
3. Results NKcellsaremainlyIFNc-producingcells.Moreover,these
two cytokines act synergistically and excessive levels con-
Pilot experiments were performed to determine cell cul- tribute to various inflammatory diseases (Krakauer et al.,
ture conditions for NHP blood cells ex vivo. Blood cells 1998). IL-2, produced by activated T cells in response to
obtained from normal NHP were stimulated with various superantigens, is used often to assess T cell stimulation
concentrationsofSEBtodefinetheoptimaldoseofsuper- (Fraser et al., 1992). Due to the individual variations of
antigen and culture time. Fig. 1a shows the variation of cytokine levels among NHP, data are expressed as a per-
cytokineresponsesfromindividualmonkeystoanoptimal centage of cytokine release from SE-stimulated blood cells
concentration of SEB (750ng/ml). Similar results were at time zero before initiation of drug dosing.
observedwithanothersuperantigenSEA(Fig.1b).Thedif- Wenextdeterminedthedoseofpentoxifyllinenecessary
ference in cytokine levels among NHP was also observed to achieve inhibition of cytokine release from SEB-stimu-
with human peripheral blood mononuclear cells from dif- lated blood cells ex vivo. A specific dose of pentoxifylline
ferent donors stimulated with superantigen (Krakauer, was administered orally every 8h and peripheral blood
1995). Differential binding affinities of SEB and other was taken at 3h and 27h. Whole-blood cells were stimu-
superantigens to different MHC alleles contribute to the latedwithSEBorSEAexvivofor20h.Thecytokinelevels
heterogeneous response to these superantigens (Mollick fromwhole-bloodcellstakenat3hor27hwerecompared
etal.,1991;reviewedinKrakauer,1999).Importantly,dif- to cytokines induced by SEB-stimulated cells at zero time
ferences among the cytokines TNFa, IFNc and IL-2 from before initiation of drug treatment (100%). NHP given
eachmonkeywerealsoevident.Wechosethesethreecyto- 48mg/kg and 72mg/kg of pentoxifylline did not produce
kines released by superantigen-activated cells as biomark- inhibitory effects at 3h (data not shown). Fig. 2 indicates
Fig.1. Tumornecrosisfactora(TNFa),interferongamma(IFNc)andinterleukin-2(IL-2)productionby(a)SEBand(b)SEA-stimulatedwhole-blood
cells fromnormalNHP.IndividualNHP are representedby Ato H. Supernatants were harvestedat20h for determinationof cytokines by ELISA.
Backgroundlevelsofeachcytokinefromcellsculturedinmediumalone(med)areasindicated.Dataarethemeanpg/ml±SEofduplicatesamplesand
resultsrepresenteightNHP.
T.Krakaueretal./ResearchinVeterinaryScience83(2007)182–187 185
that 48mg/kg and 72mg/kg did not have suppressive
effects at 27h, whereas attenuation of IFNc and IL-2 to
70% and 33%, respectively, was observed in ex vivo SEB-
stimulated cells when 96mg/kg of pentoxifylline was used.
AlthoughnoinhibitionofTNFawasobservedat96mg/kg
ofpentoxifylline,78%attenuationwasobservedat120mg/
kg.IFNcandIL-2weresuppressedfurtherat120mg/kgof
pentoxifylline. Compared to TNFa, IFNc and IL-2 were
more sensitive to inhibition by pentoxifylline. A similar
degree of inhibition of the three cytokines was observed
using SEA-stimulated cells at different doses of
pentoxifylline.
We also compared the effects of 120mg/kg of pentoxif-
ylline at 3h (after the first dose) and at 27h (3h after the
fourth dose) with blood cells taken from sham-treated
Fig.3. InhibitionofTNFa,IFNc,andIL-2productionbywhole-blood
cells stimulatedby SEB after oral dosing of120mg/kg pentoxifylline at
3hor27h.ResultsareexpressedasapercentageofSE-stimulatedwhole-
bloodcellculturesofNHPat0h(untreated=100%).Sham-treatedNHP
weretreatedidenticallyexceptwaterwasgiveninsteadofpentoxifylline.*
denotesastatisticalsignificantdifference(p<.05)betweenpentoxifylline
andsham-treatedgroups.
NHP at the same time points (n=4). Cytokine levels did
notchangeinsham-treatedcontrolswithbloodcellstaken
at 3 or 27h (Fig. 3). No effect of pentoxifylline was
observed at 3h, whereas inhibition of TNFa, IFNc and
IL-2 to 88%, 81% and 76%, respectively, was evident at
27h after oral dosing of 120mg/kg.
4. Discussion
Fig.2. InhibitionofTNFa,IFNc,andIL-2productionbywhole-blood TheresultspresentedhereinindicatethatSEBandSEA
cells stimulated by SEB or SEA after oral dosing of 0, 48, 72, 96, and can induce monkey whole-blood cells to produce the typi-
120mg/kgofpentoxifyllineat27h.Resultsareexpressedasapercentage
calcytokinesinducedbyhumanperipheralbloodmononu-
ofSE-stimulatedwhole-bloodcellculturesofNHPatzerotime(untreated
clear cells upon stimulation by superantigens. The use of
NHP).Datashowmeaninhibition±SE.*denotesastatisticalsignificant
difference(p<.05)betweenpentoxifyllineanduntreatedgroups. whole-blood cells ex vivo affords the evaluation of drug
186 T.Krakaueretal./ResearchinVeterinaryScience83(2007)182–187
doses and effects on NHP, an animal model much more Fraser,J.,Newton,M.,Weiss,A.,1992.CD28andT-cellantigenreceptor
akintohuman.Moreover,thebiologicaleffect(s)ofagiven signal transduction coordinately regulates interleukin 2 gene expres-
sioninresponsetosuperantigenstimulation.JournalofExperimental
drug is a more powerful tool in examining drug efficacy
Medicine175,1131–1134.
thanotherparametersandwillaidinthediscoveryofdrug
Fraser,J.,Arcus,V.,Kong,P.,Baker,E.,Proft,T.,2000.Superantigens–
targeting specific diseases when surrogate markers of dis- powerfulmodifiersoftheimmunesystem.MolecularMedicineToday
easesareavailable.Forthefirsttime,thisstudyuseswhole 3,125–132.
bloodcellsexvivotoevaluatedrugpotencyinNHPbased Geller-Hong,E.,Gupta,G.,2003.Therapeuticapproachestosuperanti-
gen-baseddiseases:areview.JournalofMolecularRecognition16,91–
on the biological response to a specific biotoxin.
101.
Pentoxifyllinehaslongbeenusedclinicallyforthetreat-
Hodoval, L.F., Morris, E.L., Crawley, G.J., Beisel, W.R., 1968. Patho-
mentofperipheralarterialdisease(RegensteinerandHiatt, genesisoflethalshockafterintravenousstaphylococcalenterotoxinB
2002). Peak plasma levels of pentoxifylline as well as its inmonkeys.AppliedMicrobiology16,187–192.
metabolitesarereachedwithin1h(Physicans’DeskRefer- Kotzin, B.L., Leung, D.Y.M., Kappler, J., Marrack, P., 1993.Superan-
tigens and their potential role in human disease. Advances in
ence 2005). The plasma half-life of pentoxifylline and its
Immunology54,99.
metabolites variesfrom 0.4to1.6h.Thus theexvivoanti-
Krakauer, T., 1995. Inhibition of toxic shock syndrome toxin-induced
cytokine effects of pentoxifylline seen in this study is likely cytokineproductionandTcellactivationbyinterleukin10,interleukin
a result of its immunosuppressive effects on drug-treated 4,anddexamethasone.JournalofInfectiousDiseases172,988.
cellsinvivoasitsplasmapharmacokineticsindicatesrapid Krakauer, T., 1999. Immune response to staphylococcal superantigens.
ImmunologicalResearch20,163–173.
clearance.Althoughtheeffectofpentoxifyllineinmicrocir-
Krakauer, T., 2005. Chemotherapeutics targeting immune activation by
culationiswellknown,itsuseinmodulatinginflammation
staphylococcalsuperantigens.MedicalScienceMonitor11,290–295.
has recently been investigated in various in vitro and Krakauer, T., Stiles, B.G., 1999. Pentoxifylline inhibits superantigen-
invivomodelsofacuteinflammation(KrakauerandStiles, induced toxic shock and cytokine release. Clinical Diagnostic Labo-
1999;Bell,2005;Whitehouse,2004).Inthepresentstudy,we ratoryImmunology6,594–598.
Krakauer, T., Stiles, B.G., 2006. Staphylococcal and streptococcal
assesseditseffectivenessintargetingtheimmunologicalacti-
superantigens. In: Swearengen, J.R. (Ed.), Biodefense Research
vatingeffectsofabacterialsuperantigeninNHP.
Methodology and Animal Models. Taylor and Francis Publishers,
In summary, we evaluated the anti-inflammatory BocaRaton,pp.291–391.
potency of pentoxifylline by oral dosing NHP and per- Krakauer, T., Vilcek, J., Oppenheim, J.J., 1998. Proinflammatory cyto-
formed ex vivo measurement of cytokine release from kines:TNFandIL-1families,chemokines,TGFbandothers.In:Paul,
W. (Ed.), Fundamental Immunology. Lippincott-Raven Publishers,
superantigen-stimulatedwhole-bloodcellstakenatvarious
Philadelphia,pp.775–811.
intervalsafterdifferentoralregimens.Suppressionofcyto-
McCormick, J.K., Yarwood, J.M., Schlievert, P.M., 2001. Toxic shock
kineresponsewasnotobservedatlowerdosesofpentoxif- syndromeandbacterialsuperantigens:an update.AnnualReviewof
ylline (48mg/kg, 72mg/kg) at either 3h or 27h after Microbiology55,77.
initiationofthefirstdose.Wefoundthat96mg/kgofpen- Miethke, T., Wahl, C., Heeg, K., Echtenacher, B., Krammer, P.H.,
Wagner,H.,1992.Tcell-mediatedlethalshocktriggeredinmicebythe
toxifylline given orally to NHP effectively inhibited SEB-
superantigen staphylococcal enterotoxin B: critical role of tumor
induced IFNc and IL-2 in exvivo culturesof NHP whole-
necrosisfactor.JournalofExperimentalMedicine175,91–98.
blood cells at 27h. Thus the measurement of cytokine Miethke, T., Wahl, C., Heeg, K., Echtenacher, B., Krammer, P.H.,
release from stimulated whole-blood cells of NHP after Wagner, H., 1993. Superantigen mediated shock: a cytokine release
initiationofdrugtreatmentprovidesaconvenientandmea- syndrome.Immunobiology189,270–284.
Mollick, J.A., Chintagumpala, M., Cook, R.G., Rich, R.R., 1991.
surablyfunctionalcorrelateofdrugpotencyanddefinesthe
StaphylococcalexotoxinactivationofTcells:roleofexotoxin-MHC
exact doseof drug necessary totargetspecific responses.
class II bindingaffinityandclass IIisotype.Journalof Immunology
146,436–468.
References
Neuner, P., Klosner, G., Schauer, E., Pourmojib, M., Macheiner, W.,
Grunwald, C., Knobler, A., Schwarz, A., Luger, T.A., Schwarz, T.,
Baker, M.D., Acharya, K.A., 2003. Superantigens: structure, function, 1994.Pentoxifyllineinvivodown-regulatesthereleaseofIL-1b,IL-6,
anddiversity.In:Krakauer,T.(Ed.),SuperantigenProtocols.Humana IL-8 and tumour necrosis factor-a by human peripheral blood
Press,Totowa,pp.1–31. mononuclearcells.Immunology83,262–267.
Bell, S.G., 2005. Immunomodulation, part I: pentoxifylline. Neonatal Parsonnet, J., 1989. Mediators in the pathogenesis of toxic shock
Network24,45–48. syndrome:overview.ReviewofInfectiousDiseases11,S263–S269.
Blank,C.,Luz,A.,Bendigs,S.,Erdmann,A.,Wagner,H.,Heeg,K.,1997. Proft, T., Fraser, J.D., 2003. Bacterial superantigens. Clinical and
Superantigenandendotoxinsynergizeintheinductionoflethalshock. ExperimentalImmunology133,299–306.
EuropeanJournalofImmunology27,825–833. Rajagopalan, G., Sen, M.M., David, C.S., 2004. In vitro and in vivo
Choi,Y.,Kotzin,B.,Hernon,L.,Callahan,J.,Marrack,P.,Kappler,J., evaluationofstaphylococcalsuperantigenpeptideantagonists.Infec-
1989.InteractionofStaphylococcusaureustoxin‘‘superantigens’’with tionandImmunity72,6733–6737.
humanTcells.ProceedingsofNationalAcademyofSciencesUSA86, Regensteiner, J.G., Hiatt, W.R., 2002. Current medical therapies for
8941–8945. patients with peripheral arterial disease: a critical review. American
Darenberg,J.,Soderquist,B.,Normark,B.H.,Norrby-Teglund,A.,2004. JournalofMedicine112,49–57.
DifferencesinpotencyofintravenouspolyspecificimmunoglobulinG Stiles, B.G., Bavari, S., Krakauer, T., Ulrich, R.G., 1993. Toxicity of
against streptococcal and staphylococcal superantigens: implications staphylococcalenterotoxinspotentiatedbylipopolysaccharide:major
fortherapyoftoxicshocksyndrome.ClinicalInfectiousDiseases38, histocompatibilitycomplexclassIImoleculedependencyandcytokine
836–842. release.InfectionandImmunity61,5333–5338.
T.Krakaueretal./ResearchinVeterinaryScience83(2007)182–187 187
Stiles,B.G.,Campbell,Y.G.,Castle,R.M.,Grove,S.A.,1999.Correlation Visvanathan, K., Charles, A., Bannan, J., Pugach, P., Kashfi,
of temperature and toxicity in murine studies of staphylococcal K., Zabriskie, J.B., 2001. Inhibition of bacterial superantigens
enterotoxins and toxic shock syndrome toxin 1. Infection and by peptides and antibodies. Infection and Immunity 69, 875–
Immunity67,1521–1525. 884.
Trede,N.S.,Geha,R.S.,Chatila,T.,1991.Transcriptionalactivationof Whitehouse, M.W., 2004. Anti-TNF-alpha therapy for chronic inflam-
IL-1 beta and tumor necrosis factor-alpha genes by MHC class II mation: reconsidering pentoxifylline as an alternative to therapeutic
ligands.JournalofImmunology146,2310–2315. proteindrugs.Immunopharmacology12,211–217.