The sensitivity of<Emphasis Type="Italic">Escherichia coli</Emphasis> strains with K1 surface antigen and rods without this antigen to the bactericidal effect of serum

The susceptibility of Escherichia coli strains with K1 surface antigen (K1+) and rods without this antigen (K1-) to the bactericidal action of normal bovine serum and human normal cord serum was determined. Seventy E. coli strains (35 K1+ and 35 K1-) were isolated from urine obtained from children with urinary tract infections. The strains investigated showed variable sensitivity to the bactericidal action of the sera. E. coli K1+ strains were characterized by lower sensitivity to bactericidal effect of the sera in comparison with K1- rods. The role of the particular mechanisms of complement activation in the process of killing of the E. coli strains was also determined.     

Bactericidal activity of normal cord serum (NCS) against Gram-negative rods with sialic acid-containing lipopolysaccharides (LPS)

Sialic acids, that are important constituents of animal tissue glycoconjugates, are also present in antigens of some bacterial strains. Capsular polysaccharides with sialic acid have been extensively studied whereas little is known on lipopolysaccharides which contain sialic acid. The susceptibility of Gram-negative strains with sialic acid-containing lipopolysaccharides to the bactericidal action of the sera of newborns was examined. The strains investigated showed variable sensitivity to the bactericidal action of normal cord serum.     

Influence of plasmids on bacterial susceptibility to the bactericidal activity of sera. I. Characteristic of R plasmids of enteropathogenic strains of Escherichia coli isolated from clinical cases

The 47 enteropathogenic Escherichia coli strains isolated from the cases of infant diarrhoea were characterized from the point of view of antigenic structures and drug resistance. Six R plasmids were obtained from these strains and were tested for protective activity of E. coli K12 W 1485 against lethal action of sera. Out of three sera tested, the investigated plasmids showed the most evident protective activity upon lethal action of neonatal serum. One of the plasmids appeared even more efficient than R100.1.     

Bactericidal activity of normal human serum to gram-negative rods with sialic acid containing lipopolysaccharide

The complement plays the most important role in eliminating bacterial invasion of the host, by facilitating phagocytosis of potential pathogens and by participating in the direct essential role in protecting gram-negative bacteria against bactericidal activity of serum. Sialic acids which are important constitutes of animal tissue glycoconjugates are also present in antigens of some bacterial strains. The susceptibility of gram-negative strains with sialic acid--containing lipopolysaccharides to bactericidal action sera was examined.     

The sensitivity of smooth and rough mutants ofSalmonella typhimurium to bactericidal and bacteriolytic action of serum,lysozyme and to phagocytosis

The sensitivity of smooth and rough mutants ofSalmonella typhimurium belonging to different chemotypes to bactericidal and bacteriolytic action of antibodies, complement and lysozyme was investigated. By the action of specific antibodies and complement the majority of strains was killed and in the presence of sufficient amount of lysozyme even lysed. Sera of newborn piglet which do not contain antibodies however, were able to kill regularly only strains of lower chemotypes (Rc and Rb). Smooth strains were usually resistant to the action of piglet serum whereas strains of Ra chemotype were killed only by sera of some piglets. Using the liver clearance method a significant correlation between the lipopolysaccharide chemotype of the particular strain and the degree of phagocytosis was found.     

Bactericidal activity of normal sera from various animal species against pathogenic and saprophytic leptospires

The leptospirocidal activity of 5 animal species against L. interrogans, L. biflexa and L. kazachstanica I and II, belonging to different serogroups and serovars, was studied. Cattle and sheep sera had no lytic effect on 36.9-40.1% of pathogenic Leptospira strains, but other pathogenic strains, as well as saprophytes, were lyzed by these sera. L. pomona and L. grippotyphosa exhibited high resistance to cattle serum, the latter being also resistant to sheep serum.     

Antigenic specificity of Vibrio cholerae O139 nitrosoguanidine mutants

The action of nitrosoguanidine (NG) on the culture of V. cholerae O139 P-16064 resulted in the appearance of mutant 16064 NG6, not agglutinating with commercial diagnostic serum O139. Its incapacity of agglutination was due to the sorption of the specific serum with strains V. cholerae O22 and R-variant RCA-385, which caused the loss of antibodies to common determinants. Experiments with the sorption of immune sera made it possible to suggest that one of the determinants of LPS O139, phosphate-galactose, was absent in NG mutant.     

Antibody-dependent cellular cytotoxicity detects type- and strain-specific antigens among human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus SIVmac isolates.

Human cell lines were infected with different strains of human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) as well as with a simian immunodeficiency virus SIVmac isolate and used as targets in an antibody-dependent cellular cytotoxicity (ADCC) assay. Sera from HIV-1- or HIV-2-infected subjects provided the antibody, and lymphocytes from normal donors provided the effector cells. About 60% of HIV-1 antibody-positive sera mediated ADCC when tested against any given HIV-1 isolate-infected target cell (human T-cell lymphotropic virus type IIIB, B40, A2587), and about 75% of HIV-2 antibody-positive sera mediated ADCC when tested against target cells infected with HIV-2 isolates (lymphadenopathy-associated virus type 2 and SBL-6669) or simian immunodeficiency virus from macaques. Within each type, individual sera showed different reactivity patterns, and the probability that a serum was ADCC positive was higher when it was tested against several strains. When the ADCC reactivity of sera against different strains was compared, diversity as detected by ADCC appeared to be greater among HIV-1 strains than among HIV-2 strains. For HIV-1, 54 to 67% of the sera gave concordant ADCC reactions, whereas for HIV-2 and SIVmac, 91% of the sera gave concordant results. Almost no strain-specific differences were seen between SBL-6669 and lymphadenopathy-associated virus type 2. As we determined previously, HIV-1 and HIV-2 did not cross-react in ADCC. The results indicated that HIV-1 and HIV-2 antibody-positive sera mediate both strain- and type-specific ADCC. HIV-2 antibody-positive sera seem to mediate ADCC with broader reactivity and to a higher frequency compared with HIV-1 antibody-positive sera.     

Bacteriostatic activity of serum against staphylococci

Cybulska, Janina (State Institute of Hygiene, Warsaw, Poland), and J. Jeljaszewicz. Bacteriostatic activity of serum against staphylococci. J. Bacteriol. 91:953-962. 1966.-Antistaphylococcal activity of normal serum against strains exhibiting various patterns of coagulase, clumping-factor, and staphylokinase production is not connected with the presence of these factors. Purified coagulase does not influence this property of serum. Coagulase-negative strains with clumping-factor activity grow in normal serum as typical pathogenic staphylococci. Serum bacteriostatic activity against staphylococci may be reversed by several nonspecific factors, such as sterile broth, supernatant fluids of coagulase-negative strains, and ammonium sulfate precipitates of culture supernatant fluids of various staphylococci. Immune sera with a high agglutinating titer for staphylococcal cells do not prevent growth of serum-resistant strains; serum-susceptible strains are inhibited as in normal serum control. Activation or blocking of the serum fibrinolytic system does not influence serum bacteriostatic activity. The growth rate of serum-resistant strains is identical in serum and in Todd-Hewitt broth; serum-susceptible strains are inhibited to the inoculum level, but decreases and increases in viable count are noted during a 24-hr observation period. Observations made with sera of 10 animal species clearly demonstrated differences in serum bacteriostatic activity, mouse serum being completely noninhibitory and cat serum only weakly inhibitory. The technique of quantitative determination of serum susceptibility of staphylococci is described, and the importance of serum antistaphylococcal activity in vitro is discussed. Experimental staphylococcal infection produced in rabbits by intravenous injection of different Staphylococcus aureus strains did not result in significant changes in serum antistaphylococcal activity. The technique of experimental infection used caused chronic infection, with a peak on the 14th day; this was proved by means of a newly developed 5'-nucleotidase test. At the same time, sera of infected animals exhibited slight inhibitory properties, which returned to initial values 1 week later. Infection was produced by strains recognized as nonpathogenic and was inhibited in vitro by sera from both normal and infected rabbits. It is concluded that antistaphylococcal activity of serum should be considered as an "in vitro" phenomenon, which seems to have no importance in defense mechanisms of rabbits infected intravenously with staphylococci.     

Bactericidal activity of human sera with a physiologic or genetic defect of the complement system

The serum of patient suffering genetically conditioned C2 defect showed a weak bactericidal activity against Pseudomonas aeruginosa strains. Out of 23 tested strains one was susceptible comparing with 16 ones sensitive to normal human serum. The normal cord serum exerted a bactericidal effect on 8 strains. All sera were found to be active against Salmonella strains tested.     

Stimulation by normal and leukemic mouse sera of colony formation in vitro by mouse bone marrow cells

Using a modification of the agar gel method for bone marrow culture, serum from various strains of mice has been tested for colony stimulating activity. Ninety percent of sera from AKR mice with spontaneous or transplanted lymphoid leukemia and 40–50% of sera from normal or preleukemic AKR mice stimulated colony formation by C57B1 bone marrow cells. Sera from 6% of C3H and 30% of C57B1 mice stimulated similar colony formation. The incidence of sera with colony stimulating activity rose with increasing age. All colonies were initially mainly granulocytic in nature but later became pure populations of mononuclear cells. Bone marrow cells exhibited considerable variation in their responsiveness to stimulation by mouse serum. Increasing the serum dose increased the number and size of bone marrow cell colonies and with optimal serum doses, 1 in 1000 bone marrow cells formed a cell colony. Preincubation of cells with active serum did not stimulate colony formation by washed bone marrow cells. The active factor in serum was filterable, non-dialysable and heat and ether labile.     

Bactericidal activity of human, swine and cattle serum against pseudomonas aeruginosa strains

The aim of this study was to assess of bactericidal activity of human, swine and cattle serum against 136 of Pseudomonas aeruginosa strains isolated from people, fishes, domestic and fur animals. The mechanism of the bactericidal activity of serum against gram-negative bacteria is complex and involves the participation of complement, antibodies and lysozyme (1, 5, 7, 8, 10, 11, 13, 14, 24, 25, 27, 30). The susceptibility of gram-negative rods to serum is differentiated. Pseudomonas aeruginosa strains are the most resistant (17, 25, 30). This opportunistic pathogen produce proteases that destroy complement components and immunoglobulins (3, 18, 19). The bactericidal activity of serum was determined after 3 hours incubation of bacteria in 50% serum by the method of Jankowski (1981) (5). The results of this study indicate that 71% of this strains were resistant to swine serum action, 68% of this strains were resistant to bovine serum and 57% of the Pseudomonas aeruginosa strains were sensitive to human serum. The P. aeruginosa strains isolated from fishes were the most sensitive to serum action and the strains isolated from people and cattle were most resistant to the bactericidal activity of serum.     

Structural changes in nucleoprotein systems under the influence of serum from ill and healthy subjects]

A thermomechanical method was applied to the study of the interaction of the model desoxyribonucleoprotein systems (DNP-systems) of chromatin with the blood sera of healthy and sick persons. It was demonstrated that the blood sera of healthy persons caused decondensation of the DNP-systems. The intensity of this action varied when the sera with the composition altered as a result of pathology were used: the sera of the patients suffering from systemic lupus erythematosus increased the condensation; in comparison with the sera of healthy persons, the sera of schizophrenic patients intensified the DNP-system decondensation. The sera action was not connected with the activity of the serum enzymes. The role played by the serum components in regulation of the structural-functional chromatin properties is discussed.     

Platelet-activating factor and serum components from oestrous mice co-operate to mimic the activity of 'early pregnancy factor' in the rosette inhibition assay

When male mouse spleen cells were incubated with a combination of platelet activating factor (PAF, 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) and sera from female mice in oestrus, the cells displayed a markedly increased rosette inhibition titre (RIT) when subsequently tested in the rosette inhibition assay. Neither PAF nor oestrous mouse sera alone could induce this effect, the combined action was required. Lyso-PAF could not substitute for the PAF, nor could male mouse sera nor the sera from females in dioestrus or metoestrus substitute for the oestrous mouse serum requirement. Pro-oestrous mouse sera could replace oestrous mouse sera but were less effective in their dose-responses. Studies on the mechanism of action of the PAF and oestrous mouse serum components suggested that the PAF stimulated the production and release of soluble factors (termed S2 factors) which by themselves could induce increased RIT values when applied to fresh spleen cells. The PAF-stimulated cell populations were rendered refractory to the action of these S2 factors and did not display increased RIT values, unless oestrous mouse serum was added. This serum acted to reverse the refractory state, allowing the S2 factors to exert their effect, and so cells treated with PAF and oestrous mouse serum displayed increased RIT values.     

Blood serum as a factor of chromatin condensation in trisomy-21 (Down's syndrome)]

The influence of blood sera from patients with Down's syndrome and healthy ones, and different serum fractions on the structure of the deoxyribonucleoprotein systems (DNP-system) has been studied. It was demonstrated that non-fractionated sera of the patients produce a condensation effect on the DNP-system in contradistinction to the sera from healthy people. The analysis of the action of single serum fractions showed that different condensation effect results from the activity of high molecular nondialysable thermosensitive components whose action disappears at gel-filtration of serum proteins. A possibility of the humoral control over chromatin structural organization in vivo is discussed in terms of the evidence on the similarity of serum proteins and chromosomal nonhistone proteins.     

Bacteriological activity in unfiltered calf sera collected for tissue culture use.

Bacteriological tests were made on 24 lots of unfiltered calf serum collected for subsequent use as a component of tissue culture media. The examination included the isolation and identification of bacteria, assay of phages, and demonstration of endotoxin material. Only Gram-positive bacteria were isolated and 96% of the sera were contaminated with bacteria. The prevalent strains of bacteria found were Bacillus species and streptococci and 63% of the sera coagulated Limulus amebocyte lysate. More than 90% of the lots contained phages demonstrable with the C-3000 strain of Escherichia coli. Only one lot of the serum was found to be free from bacteria, phages, and endotoxin by the tests used.     

Neutralisation of vacuolating activity of cytotoxin by serum antibodies of Helicobacter pylori infected patients

The study involved 196 H. pylori strains and 196 serum samples taken from the same patients. H. pylori strains were investigated for the production of vacuolating cytotoxin. Antibodies to the vacuolating cytotoxin produced by H. pylori were detected in the sera samples by neutralisation assay (on Intestine 407 cells) and ELISA. Of the 196 H. pylori strains tested, 80 (40.8%) were found to express vacuolating cytotoxic activity. The titres of vacuolating cytotoxic were ranged from 1:2 to 1:128. The vacuolating assay was positive in 37.1% strains isolated from children, and in 50% strains isolated from adults. Cytotoxin-positive H. pylori strains were found more frequently in duodenal ulcer (71%) than in chronic gastritis (35.2%) patients, and this difference was statistically significant p<0.05. Neutralising antibodies to vacuolating cytotoxin were present in 51% and 49% of the serum samples tested by neutralisation and ELISA, respectively. Duodenal ulcer patients had antibodies to vacuolating cytotoxin more frequently (p<0.05) than chronic gastritis patients. Antibodies to cytotoxin were detected in 100% of the serum samples from patients infected by cytotoxic H. pylori strains. This suggests that the presence of anticytotoxic antibodies in the serum samples may be regarded as a sensitive indicator of infection by cytotoxic H. pylori strains.     

A comparison of two antigen strains of each of mouse hepatitis virus and mouse adenovirus for detection of complement fixation antibody in mouse and rat sera

Detection rates of complement fixation antibodies in mice and rats were compared between two antigen strains of each of mouse hepatitis virus (MHV) and mouse adenovirus (MAV). Among 66 and 47 naturally infected MHV-positive sera of mice (18 facilities) and rats (16 facilities) respectively, 17 mouse and 21 rat sera reacted with both Nu-67 and MHV-2 strains, but 49 mouse and 25 rat sera were positive to Nu-67 strain alone. Only one rat serum reacted with MHV-2 strain alone. In comparison with K87 and FL strains of MAV, all 8 positive mouse sera (3 facilities) reacted with K87 strain alone whereas out of 53 positive rat sera (20 facilities), 43, 6 and 4 sera reacted with K87 strain alone, with FL strain alone and with both the two strains, respectively.     

Bactericidal activity of ethanol against glucose nonfermentative Gram-negative bacilli

The bactericidal effect of ethanol on glucose nonfermentative Gram-negative bacilli (nonfermentative bacilli) and other species of micro-organisms was studied with emphasis on the former. At 20 degrees C, 10 to 20% v/v ethanol took 1 h or more to kill thirteen strains of nonfermentative bacilli while 40 to 99.5% concentrations produced a bactericidal effect within 1 min of exposure. Eleven strains of glucose fermentative organisms showed a similar tendency to that noted with nonfermentative bacilli, except that S. aureus was a little resistant to 99.5% ethanol. Using several strains of nonfermentative bacilli, the effects of temperature and equine serum on the bactericidal action of ethanol were determined. The bactericidal action of ethanol increased with rising of temperature (10-30 degrees C), and it was sufficient even at 10 degrees C provided that the concentration of ethanol was over 50%. The equine serum produced little effect on the bactericidal action of ethanol.     

Protective antibodies in human sera against encapsulated strains of Staphylococcus epidermidis

Passive protective antibodies in 100 samples of normal human sera against challenge with three representative capsular type strains of Staphylococcus epidermidis in mice were examined. Six of them passively protected mice against capsular type I; 17 protected against capsular type II; one against capsular type III; and one against both capsular types I and II. The activities were sensitive to 2-mercaptoethanol and were absorbed out either with rabbit anti-human IgG serum, rabbit anti-human IgA serum or rabbit anti-human IgM serum. Also, the sera activities absorbed out with cell surface polysaccharide extracted from three representative capsular type strains. These results indicate that the protective activities were specifically related to three major immunoglobulins against the above cell surface polysaccharides.