A role for both the cellular and humoral components of the immune response has been established for chlamydial infection. The significance of helper (L3T4) T cells was evaluated by using a Chlamydia trachomatis murine salpingitis model for upper genital tract chlamydial infection. Mouse oviducts were inoculated with C. trachomatis by using the mouse pneumonitis agent (MoPn) or control medium. Mice depleted of L3T4-bearing lymphocytes had significantly higher (P < 0.05) numbers of organisms recovered at day 7 postinoculation. The rate of hydrosalpinx formation was significantly higher in the mice depleted of L3T4-bearing lymphocytes (27 of 31 [87%]) than in the infected undepleted group (8 of 16 [50%]) (P < 0.01). The geometric mean antichlamydial immunoglobulin G titers at day 54 postinoculation were significantly higher in the L3T4depleted mice (mean titer, 2,030) than in the undepleted group (mean titer, 776; P < 0.05). The rate of fertility was lower in the L3T4-depleted group (2 of 31 [6%]) than in the infected, undepleted mice (2 of 16 [13%]), but this difference did not reach statistical significance. In conclusion, the greater persistence of organisms in the oviduct and higher rates of hydrosalpinx formation in mice depleted of L3T4-bearing cells suggests that these cells play a role in the clearing of organisms following infection and thus in reducing the degree of oviduct obstruction and damage.
Pooled human immunoglobulin suitable for intravenous administration (IGIV) was evaluated in the prophylaxis and treatment of herpes simplex virus (HSV) type 1 encephalitis in a murine model. Four-week-old BALB/c mice received a single intraperitoneal injection of IGIV or saline 24 h before or up to 24 h after intranasal infection with 10(4.6) PFU of HSV type 1. Treatment with IGIV was protective against death, and the protective effects were dose and time dependent. Treatment with IGIV blocked the production of HSV antibody by infected mice and reduced the number of trigeminal ganglia containing latent virus. Removal of neutralizing antibody from the IGIV pool did not eliminate the protective effect, whereas F(ab)2 fragments of IGIV, which had virus-neutralizing activity that was identical to that of native IGIV, conferred no protection against death. Pooled human IGIV was effective for the prevention and treatment of HSV encephalitis in mice. Antibody-mediated protection required the Fc portion of the immunoglobulin molecule but did not require the direct neutralization of virus.
Neisseria meningitidis infection results in life-threatening illnesses, including bacteremia, sepsis and meningitis. Early diagnosis and treatment are a challenge due to rapid disease progression, resulting in high mortality and morbidity in survivors. Disease can occur in healthy individuals, however, risk of infection is higher in patients with certain risk factors. N meningitidis carriage and case-fatality rates are high in adolescents and young adults. The absolute incidence of meningococcal disease has decreased partially due to increasing meningococcal vaccination rates. Maintaining protective levels of circulating antibodies by vaccination is necessary for clinical protection against disease. The Centers for Disease Control and Prevention Advisory Committee on Immunization Practices guidelines recommend vaccination for all individuals aged 11 through 12 years, followed by a booster dose at age 16 years for maintenance of protective antibody levels throughout the high-risk years. Despite these guidelines, many adolescents remain unvaccinated and susceptible to infection and disease.
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