Fig. 1: Rectal challenge model of infection in cynomolgus macaques.

Four cynomolgus macaques were challenged with MPXV IIb virus on day 0 with 1 × 107 pfu of MPXV by the rectal route. Two animals were euthanized on day 11 and two were followed for 83 days for clinical and immunological monitoring (a). Five clinical signs were monitored for 34 days (n = 2): the presence of rectal exudate, loss of appetite, presence of lesions, lymphadenomegaly, and weight loss >10% were recorded for each animal. b Viral load assessment in rectal and seminal fluids (n = 4 for rectal fluid and n = 2 for seminal plasma). MPXV DNA was quantified by qPCR and is expressed as viral DNA copies/mL. The lower limit of detection (LLOD) was 90,000 copies/mL, and the lower limit of quantification (LLOQ) was 100,000 copies/mL. c The rectal and seminal fluid samples containing viral DNA were tested for virus infectivity in Vero cells. Viral infectivity is quantified in pfu/mL. The LLOD was established at 10 PFU/mL, indicated by the dotted line. All samples below this LLOD were considered negative and are represented by a value of 1. d Orthopoxvirus-binding IgG concentrations are reported in arbitrary units (arb. unit./mL). Serum (left) and seminal plasma (right) from two NHPs (n = 2) were evaluated for the total anti-MPXV protein IgG concentration before challenge and at various time points up to days 62 and 83 post-challenge for serum and seminal plasma, respectively. Each symbol represents one animal, and the different shapes represent different antigens. The dashes represent the mean. Ag: antigen. Source data are provided as a Source Data file.