Kai Krohn

Immunological variation and immunohistochemical localization of HIV-1 Nef demonstrated with monoclonal antibodies.

ObjectiveTo study the immunological and immunohistochemicai nature of HIV-1 Nef. DesignMonoclonal anti-Nef antibodies were generated and used to identify antigenic epitopes in Nef, to study immunological cross-reactivity between Nef from different isolates and to reveal the subcelluiar localization of Nef. MethodsMonoclonal antibodies against recombinant HIV-1 Nef protein (BRU isolate) were generated in BALB/c mice. The epitope mapping was carried out with the use of overlapping 15–20mer lipopeptides linked to a lipid group at the amino-terminus. Immunoperoxidase method was used for histochemical studies. ResultsTen stable antibody-producing clones, mainly of the immunoglobulin (Ig) G1 subtype, with strong Western blot and enzyme-linked immunosorbent assay reactivity toward the recombinant Nef protein, were obtained. The epitopes recognized were located on amino-acid sequences 21–41, 31–50, 51–71, 61–80, 151–170, 161–180, and 171–190. All 10 monoclonal antibodies also reacted with the native Nef of HIV-1BRU, and eight reacted with native HIV-1IIIB. Most antibodies also reacted with Nef from more divergent HIV-1 strains. In Western blotting, two forms of Nef (24 and 27 kDa) were observed with most isolates studied. Immunohistochemical staining of HIV-1 -infected H9 or MT-4 lymphoid cells demonstrated that Nef was expressed mainly in the Golgi complex and at the nuclear membrane, but occasionally also in the nucleus. The nuclear localization of Nef was especially frequent in the HIV-1-infected MT-4 cells. ConclusionsOur findings suggest that Nef is expressed in two isomorphic forms, and that it may also act as a nuclear protein and thus have a direct regulatory function at the RNA/DNA level.

Intensive care of small premature infants. II. Postmortem findings.

Twenty‐seven deaths in premature infants weighing less than 1 250 g who were treated with intermittent positive pressure respiration are reported. The major pulmonary abnormalities were hyaline membrane formation, infection, and hemorrhage occurring‘ alone or in combination with intraverticular hemorrhage. Hyaline membranes were associated with severe clinical features of respiratory distress, whereas infection was not. Prolonged treatment resulted in “bronchopulmonary dysplasia” in only 1 case where severe clinical respiratory distress was associated with the finding of hyaline membranes at post mortem.

Absence of some common organ-specific and non-organ-specific autoimmunity in autoimmune polyendocrinopathy candidiasis ectodermal dystrophy

Background Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is a rare autosomal recessive disorder caused by mutations of the autoimmune regulator (AIRE) gene, whose loss of function leads to the escape of self-reactive T cells from the thymus and autoimmunity. APECED patients typically develop tissue-specific autoantibodies and anti-cytokine antibodies. Consequently, various endocrine and non-endocrine autoimmune disorders appear. However, only a certain number of autoimmune diseases develop, while some common autoimmune conditions have not been reported or are seen only anecdotally. Objective We investigated the clinical manifestations and occurrence of antinuclear antibodies (AN-Abs) and antibodies against extractable nuclear antigens, citrullinated peptide, and transglutaminase in 24 patients and against bullous pemphigoid antigen 180 and desmogleins 1 (Dsg1) and Dsg3 in 30 patients of a Finnish cohort of APECED patients. Results Despite the loss of central tolerance, the autoantibodies investigated were not overrepresented among the APECED patients. None of the patients had a history of autoimmune connective tissue disease, rheumatoid arthritis, celiac disease, or autoimmune cutaneous bullous disorders. Altogether, 25% (6/24) had low-titer (1:80) AN-Abs. Two patients had anti-BP180 antibodies and two others had anti-Dsg3 antibodies without any cutaneous or mucosal symptoms. No anti-citrullinated peptide and anti-transglutaminase reactivity was found. Conclusions The mechanisms that drives tolerance to tissue autoantigens is not fully understood as even APECED patients, who are genetically prone to develop autoantibodies, are tolerant against some common autoantigens. The hypothesis that some of the anti-cytokine antibodies commonly found in APECED patients may be protective should be investigated in larger series.

Precipitating anti-adrenal antibodies in Addison's disease

Abstract Precipitating antibodies that react against two tissue-specific adrenal antigens were found in 9 out of 19 children suffering from moniliasis and hypoparathyroidism. Eleven of these children had, or developed, adrenal failure during the course of the study. The antibodies were of IgG type with a narrow electrophoretic mobility. Immunofluorescence revealed adrenal antibodies in all of the cases with precipitating antibodies, in five additional cases with moniliasis and hypoparathyroidism, and in two children with Addisons disease alone. Correlation of clinical and immunological data suggest that the presence of precipitating adrenal antibodies may be characteristic of the moniliasis-hypoparathyroidism complex and that in this disease group, adrenal antibodies frequently precede the manifestation of adrenal failure.

A Microangiography Study of the Fetal Arterial Vasculature in the Human Placenta in Uncomplicated Pregnancy

Abstract. The fetal arterial vasculature of 36 normal human placentas was studied by microangiography. There are two fairly readily distinguishable types of intracotyledonary artery. The first intracotyledonary artery (type A) is long and narrow and runs straight from the chorionic space towards the decidua. Its branches run within the same stem in the same or the opposite direction. The second intracotyledonary artery (type B) is thicker and twisted, and its branches extend perpendicularly from the stem. According to the distribution of these two types of arteries, three different groups of cotyledons were distinguished—those with only type A arteries, those with only type B arteries, and those with both types of intracotyledonary arteries. In these mixed cotyledons the type B arteries were always situated in the middle of the cotyledon. A fourth cotyledonary group was also distinguished; it was composed of an irregular mixture of different types of arteries, which could often only be classified with difficulty. Recurrent anchoring arteries could definitely be demonstrated. These were always branches of type B intracotyledonary arteries. In 5 of the 36 placentas spiralling involved almost all the fetal placental arteries.