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T Hjort

Publications and source records attributed to T Hjort.

At least 19 recordsLinked to original sources
PubMed1999

X-ray microscopy of human spermatozoa shows change of mitochondrial morphology after capacitation.

Using X-ray microscopy two morphologically distinct states were observed of the human spermatozoan mitochondria: (i) compact and tightly wrapped around the axoneme, and (ii) morphologically transformed, i.e. with circular areas of high X-ray transmission, either loosely wrapped around the axoneme or distended. The spermatozoa were examined at two stages of their post-ejaculation maturation process, i.e. as present in fresh ejaculated semen and after in-vitro capacitation. X-ray microscopy allowed sample preparation that was as simple as for conventional light microscopy whilst giving high resolution (30 nm) imaging of samples in liquid media compatible with the requirements of live biological specimens. The specimens were not fixed, stained or metal coated. These features make X-ray microscopy useful in the study of cells, particularly cells in suspension. The relative frequencies of the two morphological states of the mitochondria in seminal plasma and after in-vitro capacitation were compared. In seminal plasma, almost all spermatozoa had compact and tightly wrapped mitochondria. After harvesting by swim-up technique, an increase in the morphologically transformed state had occurred. However, the greatest increase in the morphologically transformed state occurred when the sample had been incubated under capacitating conditions. In this case almost all spermatozoa had morphologically transformed mitochondria.

Humans↗
PubMed1998

Do autoantibodies to sperm reduce fecundity? A mini-review in historical perspective.

PROBLEM: The paradox that early studies of antisperm antibodies in men showed a strong correlation between titers of circulating antibodies (essentially immunoglobulin [Ig] G) and reduction in conception rates, whereas more recent studies have indicated that the antifertility effect is mainly (or exclusively?) associated with IgA antibodies, impairing sperm migration through cervical mucus, was studied. METHOD OF STUDY: Relevant literature focusing on antibodies on ejaculated sperm was analyzed. RESULTS: Direct mixed antiglobulin reaction (MAR) and immunobead-binding tests are excellent and sensitive techniques for demonstrating antibodies of the IgG and IgA classes on sperm, and they have revealed that IgA antibodies are, with very rare exceptions, found only when IgG antibodies are also present. However, these tests tell little about the amounts of antibodies present, and attempts to measure quantitatively the amounts of Ig on sperm have indicated higher levels of IgA than IgG (despite the strongest MAR reactivities for IgG). CONCLUSIONS: The patients with high levels of IgA to their sperm are mainly men with strong immune responses and, therefore, also high antibody titers in serum. Apparently, the locally produced IgA antibodies reach the sperm and occupy the binding sites before the main bulk of IgG reaches the seminal compartment with the prostatic fluid.

Autoantibodies↗
PubMed1996

Quantitative determination of IgG and IgA on sperm from infertile patients with and without antisperm antibodies.

Immunoglobulins on patients sperm were determined by an ELISA technique, modified from the RIA described by Haas and D'Cruz (Am J Reprod Immunol, 1989; 20:37-43), i.e., suspensions of washed sperm (40, 20, 10, and 5 mill/ml) were added to a dilution of peroxydase-labelled anti-IgG or anti IgA, and after incubation the supernatants were transferred to cups in microtrays, coated with IgG or IgA, respectively. After incubation and washing ELISA reaction was carried out. Known amounts of IgG and IgA were processed in the same way to obtain a standard curve, allowing the Ig on the sperm to be expressed in ng/mill sperm. Ejaculates with increased viscosity revealed high values, irrespective of MAR-results and in some cases the same was true for samples with large numbers of non-spermatozoal cells (NSC). However, among 48 samples from men from infertile couples with negative MAR, > 20 mill sperm/ml, normal viscosity, and a ratio between sperm and NSC > 5, the median for IgG was 0.2 ng/mill sperm, 90% had < or = 0.8 ng/mill sperm, and the highest value recorded was 1.9 ng/mill sperm. For IgA the median was 0.5 ng, 90% of the 47 samples contained < or = 1.9 ng, and the highest value was 3.1 ng/mill sperm. The values for sperm from patients with a positive MAR, but without free antibodies in seminal plasma, were generally within the normal range. In contrast, increased values were recorded for most of the patients with free antibodies in seminal plasma, up to 4.2 ng/mill sperm for IgG and up to 12.5 ng/mill sperm for IgA.

Antibodies↗
PubMed1992

[Immunoreactivity of Mycoplasma hominis PG21 antigens and human sperm antigens].

The authors selected from the WHO bank for reproductive immunology ten sera containing concurrently antispermatozoal antibodies and antibodies against Mycoplasma hominis PG21. By absorption examination of selective sera with a different concentration (10(9)/ml, 3.10(8)/ml, 10(8)/ml) of human spermatozoa and a rinsed sonicate of Mycoplasma hominis PG21 in dilutions of 1:20, 1:80, 1:320 the authors did not find a crossed immunoreactivity between sperm antigens and mycoplasmic antigens.

Agglutination Tests↗
PubMed1991

Antisperm antibodies on epididymal spermatozoa.

Still under debate is the location in the genital tract where antisperm antibodies transuded from serum and locally produced antibodies, respectively, become attached to the surface of the spermatozoa. The mixed antiglobulin reaction (MAR) for immunoglobulin (Ig) G, IgA, and locally produced secretory IgA (sIgA) could be carried out on motile spermatozoa from epididymis from 13 of 34 men undergoing vasovasostomy. Four months and one year after the operation the MAR was repeated on a fresh semen sample from all patients. It was found that transuded as well as locally produced antisperm antibodies were bound to spermatozoa at the epididymal level of the genital tract. The follow-up results on semen were almost identical to the results obtained with epididymal spermatozoa.

Adult↗
PubMed1990

Antisperm antibodies and fertility after vasovasostomy: a follow-up study of 216 men.

A group of 216 vasovasostomized men were tested with the mixed antiglobulin reaction for immunoglobulin (Ig)G, IgA, and secretory IgA antisperm antibodies bound to the sperm membrane. Free antisperm antibodies in serum and seminal plasma were detected with the gelatin agglutination test and the tray agglutination test. The results were related to the conception rates. In a subgroup with a pure IgG response, the conception rate reached 85.7%, whereas only 42.9% of the men who also had IgA on the sperm induced pregnancy. When 100% of the spermatozoa were covered with IgA, the conception rate was reduced to 21.7%. The combination of IgA on all sperm and a strong immune response (titer in serum greater than or equal to 256) was associated with a conception rate of zero.

Antibodies↗
PubMed1989

Reduced level of sex-specific antigen (H-Y antigen) on lymphocytes in some patients with bilateral cryptorchidism.

Sex-specific (Sxs) antigen on the surface of nucleated cells from normal human males seems to be essential for the formation of testes. The relative quantity of the antigen on lymphocytes was evaluated by absorption experiments in a complement-dependent cytotoxicity test or in an ELISA technique using antisera against Sxs antigen produced by immunization of female rats. Lymphocytes from 13 normal males were Sxs-antigen positive, and cells from 12 normal females were characterized as Sxs-antigen negative. However, in the testing of lymphocytes from nine boys with bilateral cryptorchidism, only six revealed a normal male absorption pattern, whereas the antigen level on cells from three boys, all of them with normal karyotype, was reduced compared with the normal male level. No correlation between Sxs-antigen level and testosterone response after treatment with hCG could be demonstrated.

Adult↗
PubMed1988

Anti-sperm antibodies and immune subfertility.

A brief description of immune subfertility, caused by antibodies directed against sperm-specific glycoproteins in the sperm membrane, is given. Observations during the last few years have indicated that this immune disease is primarily caused by anti-sperm antibodies of the IgA class, and recent results from vasovasostomized men lend further support to this theory. Detection of anti-sperm antibodies should therefore include characterization of the immunoglobulin class of antibodies. In male patients this can be achieved by direct mixed anti-globulin reaction test or immunobead-binding test on the patients' spermatozoa, and in female patients cervical mucus can be tested by indirect versions of the same tests.

Antibodies↗
PubMed1987

Autoantibodies against spermatozoal antigens detected by immunoblotting and agglutination. A longitudinal study of vasectomized males.

Sera taken pre- and post-operatively at regular intervals within a year from 16 men undergoing vasectomy were analysed for autoantibodies against spermatozoal proteins by immunoblotting. The reaction patterns were compared with the results of sperm agglutination tests. Immunoblotting revealed the presence of autoantibodies against various spermatozoal polypeptides in all sera taken pre-operatively and post-operatively. On average, seven polypeptides showed reaction. During the post-operative period two patients developed spermatozoal agglutinins in moderate titers (greater than 16) but in immunoblotting no change in band reactivity was observed for these two patients. However, scanning of the immunoblotting results revealed that one of the patients, although without sperm agglutinins, during the post-operative period showed an increasing band colouring of a polypeptide of Mr 31,500, reflecting an increased level of the corresponding antibodies.

Adult↗
PubMed1986

Detection of autoimmunity to sperm: mixed antiglobulin reaction (MAR) test or sperm agglutination? A study on 537 men from infertile couples.

Two different ways of testing for antisperm antibodies were compared: the mixed antiglobulin reaction (MAR) test for demonstration of antibodies of the IgG and IgA classes bound in vivo to the sperm membrane antigens and the gelatin agglutination test for detection of nonbound antisperm antibodies in serum and seminal plasma. Samples from 537 men from infertile couples were investigated. Antibodies bound to the sperm membrane were detected in 49 men (9.1%), IgG in 44 (8.2%), and IgA in 38 cases (7.1%). Sperm agglutinins were recorded in seminal plasma from 30 men (5.6%) and in serum (titer greater than or equal to 16) from 43 men (8.0%). The investigation revealed a very close correlation between the results of MAR testing and the occurrence of sperm agglutinins in serum and seminal plasma. However, if one focuses on antisperm antibodies of the IgA class, which seem to play the major role in male immune infertility, the MAR test offered the advantage that a minor group of patients with pure IgG responses could be distinguished, and rare cases with mainly or exclusively locally produced IgA antibodies could be detected.

Autoantibodies↗
PubMed1986

A prospective study of antisperm antibody development in acute epididymitis.

The association between acute epididymitis and development of antisperm antibodies was investigated by the gelatin agglutination technique in prospectively collected serum samples from 27 patients. Agglutinating antisperm antibodies, mainly of the IgG class, were detected in seven men (27 per cent), a significantly increased frequency compared to prevalences previously found among blood donors and men from infertile couples. The antibodies developed de novo in four patients (15 per cent). The increased incidence of positive sera and the kinetics of the antibody responses strongly indicate a causal link between acute epididymitis and autoimmunization against spermatozoa. In the majority of the patients the antibody titers were low, being of only theoretical importance in respect to later fertility.

Adult↗
PubMed1985

The identification of candidate antigens for the development of birth control vaccines. An international multi-centre study on antibodies to reproductive tract antigens, using clinically defined sera.

In an attempt to identify appropriate antigens for birth control vaccines, the Task Force on Immunological Methods for Fertility Regulation under WHO's Special Programme of Research, Development and Research Training in Human Reproduction carried out an investigation of naturally occurring immune responses to reproductive tract antigens which were consistently associated with infertility. Large volumes of sera from subjects satisfying the criteria for one of 16 different clinical categories (listed in Table 1) were collected and samples were subsequently assessed, under code, by investigators with experience in the detection of antibodies to antigens involved in the reproductive process. Sera from 329 persons were included in the study and 20 laboratories examined the sera for antibodies to sperm, zona pellucida, and trophoblast or trophoblast products. In addition, antibodies to certain microbial antigens and to various leucocyte and organ antigens were investigated. The results of these studies are presented in the following papers.

Antibodies↗
PubMed1985

Anti-sperm antibodies, detected by agglutination, immobilization, microcytotoxicity and immunobead-binding assays.

To determine the reliability of tests currently utilized in the detection of sperm-reactive antibodies, sera were provided as unknowns and studied without knowledge of the clinical histories. Four laboratories performed tray agglutination tests (TAT), three complement-dependent immobilization (SIT), and single laboratories sperm cytotoxicity (SCT), passive haemagglutination (PHA) and immunobead binding (IBB). Most investigators demonstrated an excellent correlation between duplicate sample results. Nearly all of the female sera were free of anti-sperm antibodies and positive results did not appear in greater frequency in women with unexplained infertility as compared with other categories. For the male sera, the highest incidence of anti-sperm antibodies in the infertile group (21% positive for sperm-reactive IgGs) was obtained by immunobead binding. The GAT and TAT results gave 7 and 12% positives, except for lower results in one laboratory. Sperm-reactive antibodies were detected most commonly in vasectomized men, with all assays except SCT and PHA. Of the newer techniques studied, IBB results correlated well with TAT, GAT and SIT, while SCT and PHA did not, suggesting that a different group of antibodies, perhaps directed against other sperm-associated antigens, was being detected by the latter procedures. In this light, emphasis was placed on the need to validate whether results of particular methodologies correlated with impaired sperm function and to develop methods that provided evidence for this premise, either on the basis of clinical criteria or altered gamete interaction in vitro.

Antibodies↗