A study was conducted to characterize caprine mycoplasma species and to know its prevalence in different areas of Pakistan during 2006 to 2007. For this purpose a total of 1440 different samples such as nasal discharge, pleural fluid, lung piece, synovial fluid, and milk samples (1180), and 260 serum samples were collected from clinically affected goats of different breeds, age and sex. These samples were collected from twelve districts including Mansehra, Peshwar, Swabi, Kohat, Abbottabad, Dera Ghazi Khan, Quetta, Pishin, Jhang, Sargodha, Lahore and Faisalabad with 6 union councils (UC) in each district. Twenty samples of different nature were collected from each of union council. These samples were subjected to cultural isolation, Growth inhibition test (GIT) using rabbit polyclonal antiserum against Mycoplasma mycoides subspecies capri, latex agglutination test (LAT) for the detection of Mycoplasma capricolum subspecies capripneumoniae and polymerase chain reaction (PCR). One twenty one samples out of 1180 showed turbidity in PPLO broth whereas out of these 121 samples 58 grew on PPLO agar. All 58 field isolated organisms showed positive reaction to GIT. None of the serum sample showed a positive reaction with LAT kit. Thirty five samples out of 1180 prior to culturing were positive for Mycoplasma mycoides cluster through PCR and identified as Mycoplasma mycoides subsp. capri (Mmc) through DNA sequencing, whereas 58 samples were positive with this technique after culturing. Prevalence of mycoplasmosis in hilly and plain areas (5.8 and 4.5 % respectively) is not significantly higher as compared to semi desert and sub hilly areas (3.3 and 2.9 % respectively) which may be due to chance alone. Furthermore, the adult group-3 (age > 1 year) has significantly lowest prevalence (2.7 %) of Mmc as compared to age group-1 (age < 181 days) with 5.1 % prevalance and age group-2 (age: 181 to 365 days) with 4.4 % prevalence. This difference may be due to chance but not areal difference. Similarly prevalence (4.7%) of mycoplasmosis in female goats is not significantly higher as compared to males (3.2%). Beetal, Piamiri, Beetal teddy cross, Baltistani and Desi breeds of goats showed higher prevalence only by chance as compared to other breeds in the areas under study. Saponin inactivated vaccine was prepared from this field strain and found to be effective against Mycoplasma mycoides subsp. capri in goats. This study focuses on characterizing the interaction of M. ovipneumoniae with ovine PBMC using carboxy-fluorescein-succinimidyl-ester (CFSE) loading and flow cytometry to measure lymphoid cell division. M. ovipneumoniae induced a strong in vitro polyclonal suppression of CD4+, CD8+, and B blood lymphocyte subsets. The suppressive activity could be destroyed by heating to 60 ºC, and partially impaired by formalin and binary ethyleneimine treatment that abolished its viability. The activity resided on the surface-exposed membrane protein fraction of the mycoplasma, since mild trypsin treatment not affecting viability was shown to reduce suppressive activity. Trypsintreated mycoplasma regained suppressive activity once the mycoplasma was allowed to re-synthesize its surface proteins. Implications for the design of vaccines against M. ovipneumoniae are discussed.