Table 2: Historical NHP PID models and the pathological features found with each subsequent trial.

Researcher, YearAnimalChlamydial inoculumSite of inoculationPathologic features

Thygeson and Mengert 1936 [11]BaboonMaterial from infant with inclusion blennorrheacervixCervicitis, purulent cervical discharge
Alexander et al., 1967 [31]Taiwan monkeyTRICcervixMild erythema of the lower genital tract
Ripa et al., 1979 [32]GrivetCt, 2 × 105 IFU/mLfallopian tubeHistological changes in the upper genital tract, swollen reddened tubes, abundant lymphocytes in the tubal epithelium, clusters of desquamated cells, adhesions between mucosal folds
Johnson et al., 1980 [20]MarmosetCt, 5 × 105 IFU/mLvaginaAcute inflammatory reaction of the lower genital tract, PMNs, intracytoplasmic chlamydial inclusions
Moller et al., 1980 [33]GrivetCt, 2 × 105 IFU/mLcervixReddened and swollen tubes, exudate from ostia, histological changes in the upper genital tract, lumen of tube diminished and tubal epithelium atrophic and flattened, demonstrated vertical spread of organism
Johnson et al., 1981 [34]MarmosetCt, 4.2–8.8 × 105 IFU/mLvaginaDemonstrated that reinfection with either homologous or heterologous strain could result in infection however the shorter duration between inoculations resulted in marked immunity and decreased duration of infection
Johnson et al., 1985 [35]MarmosetCt, 5 × 105 IFU/mLvaginaCervical erythema with occasional edema, cloudy, or purulent mucus, PMNs identified, endometritis, and salpingitis
Patton et al., 1983, 1984 [36, 37]Pigtailed macaqueCt, 6 × 106 IFU/mLfallopian tubeAcute salpingitis with marked edema and swelling, flocculent exudate, PMNs, isolation of Ct from cervix and tubes
Patton et al., 1987 [38]Cynomolgus
rhesus
Ct, 7 × 106 IFU/mLSubcutaneous pocket model with fallopian tube implantsMarked erythema, edema, and swelling, widespread inflammation with lymphocytic cells and PMNs, and plasma cells had infiltrated the stroma, infection duration shorter than that seen in intact model with direct tubal inoculation
Patton et al., 1987 [14]Pigtailed macaqueCt, 2–4 × 108 IFU/mLfallopian tubeChronic salpingitis with extensive tubal scarring, distal tubal obstruction, and peritubal adhesions
Patton et al., 1990 [39]Pigtailed macaqueCt, 1 × 106 IFU/mLcervixAcute and chronic salpingitis, peritubal adhesions
Wolner-Hanssen et al., 1991 [40]Pigtailed macaqueCt, 1 × 106 IFU/mLcervixDemonstrated that repeated cervical inoculation resulted protective immunity though there was no relationship between the antibody titer and reinfection
Patton et al., 1994 [41]Pigtailed macaqueCt, 5 × 103 IFU/mLSubcutaneous pocket model with fallopian tube implantsDemonstrated a delayed hypersensitivity in response to inoculation with Ct in both previously infected pockets and noninfected pockets
Van Voorhis et al., 1997 [42]Pigtailed macaqueCt, 1 × 105 IFU/mLSubcutaneous pocket model with fallopian tube implants, cervix and fallopian tubesSuggests that a Th1-like cytokine response is seen with repeated infection with Ct
Patton et al., 2005 [43]Pigtailed macaqueCt, 1 × 105 IFU/mLcervixDemonstrated the azithromycin treatment in Ct infection ameliorated the immune response to Ct infection
Patton et al., 2008, 2009 [44, 45]Pigtailed macaqueCt, 5 × 105 IFU/mLvaginal fornix, rectumDemonstrated the ability of NHP PID model for evaluating the safety and efficacy of topical microbicides
Bell et al., 2010 [21]Olive baboonCt, 1 × 107 IFU/mLcervixAcute and chronic salpingitis, peritubal adhesions

Ct: Chlamydia trachomatis.