Anti-A and anti-B titers, age, gender, biochemical parameters, and body mass index in Japanese blood donors.

It has been reported that anti-A and anti-B (ABO antibody) titers decrease with age, but little is known about the association between ABO antibody titers and physiologic/biochemical parameters such as body mass index (BMI), gamma-glutamyl transpeptidase (GGT), and total cholesterol (T-Cho). We investigated the present situation of ABO antibody titers among healthy blood donors in Japan and the physiologic/biochemical factors that may be associated with changes in ABO antibody titers. Plasma from 7450 Japanese blood donors was tested for ABO antibody titers using ABO reverse typing reagents by an automated microplate system; donor samples were classified into low, middle, and high titers according to the agglutination results obtained with diluted plasma samples. Multivariate regression analysis was performed to analyze the association between ABO antibody titers and age, gender, biochemical parameters (alanine transaminase [ALT], GGT, globulin, T-Cho, and glycosylated albumin [GA]), and BMI according to the ABO blood groups. A significant correlation between ABO antibody titers and age/gender, except for gender in anti-A of blood group B donors, was observed. BMI showed significant but negative correlations with anti-A and anti-B (ß = -0.085 and -0.062, respectively; p < 0.01) in blood group O donors. In addition, significant but negative correlations between GGT and T-Cho with anti-B of blood group A donors (ß = -0.055 and -0.047, respectively; p < 0.05) were observed. Although differences existed among the ABO blood groups, ABO antibody titers seem to be associated with physiologic and biochemical parameters of healthy individuals.

Arginine-rich peptides. An abundant source of membrane-permeable peptides having potential as carriers for intracellular protein delivery.

A basic peptide derived from human immunodeficiency virus (HIV)-1 Tat protein (positions 48-60) has been reported to have the ability to translocate through the cell membranes and accumulate in the nucleus, the characteristics of which are utilized for the delivery of exogenous proteins into cells. Based on the fluorescence microscopic observations of mouse macrophage RAW264.7 cells, we found that various arginine-rich peptides have a translocation activity very similar to Tat-(48-60). These included such peptides as the d-amino acid- and arginine-substituted Tat-(48-60), the RNA-binding peptides derived from virus proteins, such as HIV-1 Rev, and flock house virus coat proteins, and the DNA binding segments of leucine zipper proteins, such as cancer-related proteins c-Fos and c-Jun, and the yeast transcription factor GCN4. These segments have no specific primary and secondary structures in common except that they have several arginine residues in the sequences. Moreover, these peptides were able to be internalized even at 4 degrees C. These results strongly suggested the possible existence of a common internalization mechanism ubiquitous to arginine-rich peptides, which is not explained by a typical endocytosis. Using (Arg)(n) (n = 4-16) peptides, we also demonstrated that there would be an optimal number of arginine residues (n approximately 8) for the efficient translocation.

Stearylated arginine-rich peptides: a new class of transfection systems.

Membrane-permeable arginine-rich peptides, such as HIV-1 Tat-(48-60), HIV-1 Rev-(34-50), and flock house virus (FHV) coat-(35-49), have been shown to possess the ability to transfect COS-7 cells with luciferase-coding plasmid as efficiently as polyarginine (MW 5000-15 000) and polylysine (MW 9800). Not only these virus-derived cationic peptides but also oligoarginines of 4-16 residues were found to be able to transfect cells. In the case of the Tat, FHV, and octaarginine peptides, N-terminal stearylation of the peptides increases the transfection efficiency by approximately 100 times to reach the same order of magnitude as that of LipofectAMINE, one of the most efficient commercially available transfection agents. Also, a certain correlation was observed between the transfection efficiency of stearyl-(Arg)n peptides (stearyl-Rn: n = 4, 8, 12, 16) and the membrane permeability of the corresponding (Arg)n peptides (Rn).