Influence of antisperm antibodies in the semen on intracytoplasmic sperm injection outcome

OBJECTIVE: The aim of this study was to analyze the influence of autoantibodies against spermatozoa present in the semen on the outcome of in vitro fertilization with intracytoplasmic sperm injection (ICSI). MATERIALS AND METHODS: We performed a retrospective analysis of clinical and laboratorial data from a six year-period ICSI cycles. Screening for the presence of ASA in the semen, by using the direct immunobeads test (IBT), was available for 351 cycles. According to the percentage of antibody-bound spermatozoa in the semen, we divided the cycles in four groups: I (n = 194): 0 percent-10 percent ASA; II (n = 107): 11 percent-20 percent; III (n = 33): 21 percent-50 percent and IV (n = 17): 51 percent-100 percent ASA. Additionally, a group of 349 ICSI cycles performed with ejaculated spermatozoa from oligo/asthenozoospermic men who had insufficient number of motile sperm available for ASA screening was included for comparison. ICSI outcomes were compared among groups and included fertilization rate (2 PN), cleavage rate, cleavage velocity, embryo quality, clinical pregnancy and miscarriage rates. Data were examined statistically, with an alpha level of 5 percent considered significant. RESULTS: Fertilization, cleavage rate and velocity, percentage of good quality embryos, as well as clinical pregnancy and miscarriage rates did not differ among different ASA levels groups. ICSI outcomes in men exhibiting different levels of autoimmunity against spermatozoa did not differ from those with severely abnormal seminal parameters. CONCLUSIONS: Our data indicate that intracytoplasmic sperm injection (ICSI) outcomes are not influenced by ASA levels on sperm.

Antigen incorporation on Cryptosporidium parvum oocyst walls

Cryptosporidium parvum oocysts are the infective stages responsible for transmission and survival of the organism in the environment. In the present work we show that the oocyst wall, far from being a static structure, is able to incorporate antigens by a mechanism involving vesicle fusion with the wall, and the incorporation of the antigen to the outer oocyst wall. Using immunoelectron microscopy we show that the antigen recognized by a monoclonal antibody used for diagnosis of cryptosporidiosis (Merifluor®, Meridian Diagnostic Inc.) could be found associated with vesicles in the space between the sporozoites and the oocysts wall, and incorporated to the outer oocyst wall by an unknown mechanism

Incomplete dominance of the low antibody response to Cryptosporidium parvum antigens in mice selected for high and low antibody responsiveness

The humoral antibody response to Cryptosporidium was investigated in mice genetically selected for high (H) and low (L) antibody responsiveness. Groups of 4-5 mice from two different selections, general primary (GP) and general secondary (GS), were studied. Following immunization with Cryptosporidium parvum antigens, the maximum levels of IgG in the HGP, (X ñ SD = 1.13 ñ 0.35, N = 5) and in the HGS (0.42 ñ 0.15, N = 4) lines, and of IgM in the HGP line (0.86 ñ 0.53, N = 5) were significantly higher than those in their L counterparts (0.04 ñ 0.02, N = 5;0.05 ñ 0.02, N = 4 and 0.24 ñ 0.07, N = 5, respectively). These findings were similar to those reported for other immunogens. However, the IgG (0.22 ñ 0.05, N = 4) and the IgM (0.33 ñ 0.08, N = 4) responses to immunization of F1 (LGP x HGP) hybrids indicated an incomplete dominance of the low response, in contrast to the incomplete dominance of the high response described for many other antigens and representing an important exception. In addition, the H, L and F1 mice did not develop detectable infections when inoculated with live Cryptosporidium oocysts, supporting the view that a reduced or zero antibody production itself is not enough to permit the establishment of Cryptosporidium infection in adult mice.

The immunodominant surface antigen of Plasmodium gallinaceum is present in both the salivary gland and oocyst sporozoites

1. Monoclonal antibodies (MAbs) against surface antigens of Plasmodium gallinaceum sporozoites, an avian malaria parasite, were produced using spleen cells from mice immunized with sporozoites from mosquito salivary glands (SGS) or from midadgusts containing oocysts (OoS). 2. All of the 15 MAbs teted (11 anti-SGS and 4 anti-OoS) reacted with SGS and OoS by indirect immunofluorescence and circumsporozoiter precipitation reactions. Fourteen of these MAbs (11 anti-SGS and 3 anti-OoS) produced a Western blot (WB) patten identical to that produced with serum from mice lyperimmunized with viable intacts sporozoites. 3. All MAbs and the immune sera recognized only two polypeptide bands of approximate molecutlar weight 78 and 64KDa. 4. No difference in the WB pattern was observed when-or 12-day SGS or OoS extracts were used as antigens in WB. This antigenic similary was confirmed when the total protein extracts were visualized on silver-stained SDS-PAGE gel