Passive immunization does not provide protection against experimental infection with Mycoplasma haemofelis

Sugiarto, Sarah; Spiri, Andrea M.; Riond, Barbara; Novacco, Marilisa; Oestmann, Angelina; de Miranda, Luisa H. Monteiro; Meli, Marina L.; Boretti, Felicitas S.; Hofmann-Lehmann, Regina; Willi, Barbara

Cats in both groups showed an increase in leukocyte counts immediately after infection, followed by a significant decrease, with the nadir being reached three to four weeks pi (data not shown). There was no significant difference in leukocyte counts between the two groups during the 100-day follow-up period. The lymphocyte cell counts showed an initial increase followed by a significant decrease, with the nadir reached at day 21 pi, coinciding with the onset of peak bacteremia in cats in group A (p F < 0.0001, Figure 5A ); this pattern was less pronounced in cats in group B (p F = 0.0033, Figure 5A ). Furthermore, compared with cats in group B, cats in group A had significantly higher blood lymphocyte counts at days 3 and 35 pi (p MWU < 0.05), as well as a tendency for higher counts at day 42 pi (p MWU = 0.0553, Figure 5A ). When cat JHW3 was excluded from the analyses, the lymphocyte cell counts tended to be Mhf at day 0. Significant differences between groups are indicated with asterisks (p MWU < 0.05). The reference interval for RBC OF based on measurements in nine healthy cats is shaded grey (50% hemolysis in NaCl 0.50-0.57% w/v) [10] . RBC OF significantly changed during the course of infection in cats in group A (p F = 0.0004, significantly higher levels at days 21 and 100 pi compared with day 0 pre-inoculation, p D < 0.05), but not in cats in group B.