TABLE 4.

Summary of postvaccination protection^a

Infection model/Chlamydia species	Animal model	Ag/vaccination route	Time (days) of postvaccination challenge	Assessment after postvaccination challenge	Vaccination protection	Reference
Genital (i.v.)/C. muridarum	Mouse	Plasmid-deficient C. muridarum (CM972, CM3.1)/i.v.	98	Bacterial burden (4–45 days), pathology (day 42)	Mice vaccinated with mutant C. muridarum strains were protected against oviduct disease but exhibited bacterial burdens similar to those of wt C. muridarum-vaccinated controls.	87
Genital (i.v.)/C. trachomatis serovar D	Mouse	Plasmid-deficient C. trachomatis (L2)/i.v.	35	Bacterial burden (3–28 days), pathology (day 14)	Vaccinated mice were not protected against infection or inflammatory disease but exhibited reductions in infectious burden 3 to 7 days after challenge with wt C. trachomatis.	88
					On days 14 to 28, there was no difference between vaccinated and control groups.
Genital (i.v.)/C. muridarum	Mouse	Purified MOMP (vortexed or sonicated) plus Freund's adjuvant/i.m. and s.c.	14	Bacterial burden (day 42)	Mice immunized with vortexed MOMP plus Freund's adjuvant were significantly protected against Chlamydia challenge in terms of the number of IFUs and the length of time the mice shed viable organisms compared to sonicated-MOMP-vaccinated mice.	157
	Mouse	rCPAF plus IL-12/i.n.	30	Bacterial burden (4–30 days), pathology (12–80 days)	Vaccinated mice exhibited significant reductions in bacterial shedding as early as 8 days postchallenge compared with controls.	170
					80% of vaccinated mice successfully resolved infection by day 15. In contrast, control mice (rCPAF or IL-12) were still heavily infected by day 15. By day 18, 100% of vaccinated mice had resolved the infection.
					Vaccination reduced hydrosalpinx, oviduct dilation, and fibrosis at 80 days postchallenge.
	Mouse	rCPAF plus CpG/i.n.	30	Fertility assessment, breeding (day 80)	Mice vaccinated with rCPAF plus CpG and challenged with Chlamydia exhibited fertility similar to that of nonimmunized controls.	171
					After a secondary challenge, nonimmunized controls displayed significant reductions in fertility compared to immunized mice.
	Mouse	CTH1 plus CAF01 (adjuvant)/s.c.	42	Bacterial burden (3–35 days)	Compared to control mice, CTH1-plus-adjuvant-immunized mice exhibited significantly less vaginal bacterial shedding 7, 14, and 21 days after chlamydial challenge.	173
					Days 14 to 21 showed the most efficient protection.
	Mouse	rGlgP plus CpG/i.m.	30	Bacterial burden (7–28 days), pathology (day 60)	Immunized mice were characterized by a significant reduction of live organisms in the vagina by day 14 and a reduced severity of hydrosalpinx at 60 days postchallenge.	172
	Mouse	rMIP/i.m.	30	Bacterial burden (4–30 days), pathology (day 60)	Mice immunized with MIP and C. muridarum EBs (positive control) had significantly reduced vaginal bacterial shedding as early as 12 days after intravaginal chlamydial challenge.	174
					On day 21, most of the MIP-immunized mice exhibited dramatically reduced bacterial burdens compared with negative-control mice vaccinated with glutathione S-transferase (GST).
					Hydrosalpinx severity was less severe in MIP-vaccinated mice than in GST-immunized controls.
Genital (i.v.)/C. trachomatis serovar D	Mouse	rCT823 plus AbISCO (adjuvant) or CT144 plus AbISCO/s.c.	7	Bacterial burden (3–21 days)	Vaccination with CT823 plus adjuvant reduced cervicovaginal bacterial burdens by 10 log postchallenge compared to controls (UV-inactivated EBs).	234
					Vaccination with CT144 plus adjuvant reduced bacterial burdens by 1/2 log on day 7 and then 2- to 3-fold by days 10 and 14 compared to controls.
Genital (i.v.)/C. muridarum	Mouse	MOMP DNA plasmids/i.m.	60	Bacterial burden (7–42 days), fertility assessment, breeding (day 42)	Mice vaccinated with MOMP DNA and challenged with C. muridarum exhibited vaginal shedding and fertility rates similar to those of mice vaccinated with control plasmids.	177
Genital (i.v.)/C. trachomatis serovar D	Mouse	MOMP plus PorB DNA plasmid plus Vibrio cholerae ghost (VCG)/i.m.	21	Bacterial burden (3–24 days)	Compared to controls, VCG-MOMP/PorB-immunized mice exhibited significant differences in vaginal C. trachomatis shedding in terms of duration and intensity, and the infection was completely resolved by 2 weeks postchallenge.	182
Genital (i.v.)/C. muridarum	Mouse	PmpD and PorB DNA plasmids plus VCG/i.m.	14	Bacterial burden (3–24 days)	Mice vaccinated with VCG containing a PmpD or PorB DNA plasmid or both shed 2.5-log fewer vaginal chlamydial IFUs than controls (VCG containing an irrelevant chlamydial antigen [gD2]) at 3 days postchallenge.	183
	Mouse	Adoptively transferred BMDC that were pulsed with rMOMP in vitro/intravenous	14	Bacterial burden (day 7)	Vaccinated mice that received BMDC pulsed with rMOMP were not protected against live chlamydial challenge and had vaginal shedding similar to that of unimmunized control mice at 7 days postchallenge.	63
	Mouse	Live or inactivated (UV or heat) C. muridarum, with or without CpG/i.n.	42 (live EBs), 14 (UV- or heat-inactivated EBs)	Bacterial burden (day 6)	Vaccination with live EBs significantly reduced bacterial shedding compared to that with both UV- and heat-inactivated C. muridarum at 6 days postchallenge.	66
	Mouse	Adoptively transferred BMDC that were transfected with a recombinant adenovirus carrying the C. trachomatis serovar E MOMP gene (Ad-MOMP)/intravenous	21	Body weight (2–10 days), bacterial burden (2–10 days), pathology (day 11)	Vaccinated mice that received Ad-MOMP-transfected BMDC exhibited lower bacterial genital burdens, less pathology, and minimal loss of body weight compared to controls.	72
	Mouse	Adoptively transferred BMDC that were pulsed with UV-inactivated C. muridarum plus CpG or rCPAF plus CpG in vitro/s.c.	30	Bacterial burden (3–30 days), pathology (day 80)	Mice immunized with adoptively transferred BMDC that were pulsed with either UV-inactivated EBs plus CpG or rCPAF plus CpG demonstrated significantly reduced vaginal shedding at 15 days postchallenge and reduced oviduct pathology at 80 days postinfection compared to mock-immunized mice.	73
	Mouse	Sera from (convalescent) previously vaginally C. muridarum-infected wt mice; MAb to MOMP			CD4+ T cell- and antibody-deficient mice that had previously resolved a chlamydial infection were immunized with convalescent-phase sera. These mice exhibited decreased vaginal bacterial shedding (from >100,000 IFUs to <10 IFUs) and a shortened duration of infection compared to control mice.	102
					Immunization with a MAb specific for MOMP reduced bacterial shedding >100-fold.
Genital (i.v.)/C. trachomatis serovar E	Pig	MOMP DNA plus GM-CSF, enterotoxins (E. coli) A and B/i.n. plus i.v., i.d.	21	Bacterial burden (2–25 days), pathology (day 25)	Vaginal shedding was less in i.n. plus i.v. vaccinated pigs than in pigs that were i.d. vaccinated. However, neither group of vaccinated pigs (i.n. plus i.v. or i.d.) completely resolved the infection.	139
					Vaccinated pigs exhibited significantly fewer lesions in urogenital tissues.
	Pig	PmpG plus GNE (adjuvant) and SctC plus GNE/s.c.	41	Bacterial burden (2–23), pathology (day 23)	PmpG gave better protection than SctC after vaginal challenge with C. trachomatis, characterized by low antibody titers and minor pathology.	140
					SctC-vaccinated pigs exhibited significant pathology but more antibody production after Chlamydia challenge.
Genital (i.v.)/C. psittaci	Guinea pig	Live or UV-inactivated C. psittaci/intravenous, s.c., oral, or ocular	14	Bacterial burden (3–24 days)	All immunized animals exhibited reductions in genital infection, except for guinea pigs that received UV-inactivated Chlamydia orally and nonimmunized controls.	218
					Live compared to UV-inactivated C. psittaci immunization induced more resistance to challenge, and all routes of immunization (i.v. vs s.c. vs ocular) induced similar protective responses.

^aAbbreviations: i.v., intravaginal; i.n., intranasal; i.m., intramuscular; s.c., subcutaneous; i.d., intradermal.