Mucosal defense is provided by a number of host factors countering the specific virulence factors of the many microorganisms infecting the mucous membranes. Secretory IgA antibodies presumably play an important role. Increase of the sIgA antibodies may most advantageously be attained by parenteral immunization, following mucosal priming. This was demonstrated in a rat model, where it was also noted that antigen injection into PP induced high milk IgA antibody levels. In man, parenteral vaccination against polio increased the sIgA antibody levels in the milk of mothers previously exposed naturally to the poliovirus. The response was relatively short-lived. In the previously unexposed, there was little or no response. By contrast peroral immunization with live poliovirus vaccine did not increase, or even decrease, the milk sIgA poliovirus antibody levels. Although salivary sIgA antibodies against antigens of colonizing E. coli appear during the first days of life, they are slow to increase. This deficiency is richly compensated for by all the sIgA antibodies that are provided the baby through the milk. No transfer of dimeric IgA into the milk could be shown in lactating rats, in contrast to what has been reported in mice. There is no evidence for a contribution to milk sIgA from serum in man. Close to parturition, human milk often contains some 7S IgA and various sizes of free SC, in addition to the dominating 11S sIgA. A few days later there is almost exclusively monomeric SC and 11S sIgA. IgG antibodies also play a role at the mucosal level. IgG2 antibodies against the bacterial polysaccharide capsule are as slow to appear as sIgA in ontogeny, possibly explaining the prevalence of infections with encapsulated bacteria and the poor response to polysaccharide vaccines in early childhood. Other defense factors preventing infections by way of mucous membranes may be important. Thus, oligosaccharides present in human milk seem to specifically prevent pneumococcal attachment to retropharyngeal cells. This anti-attachment capacity, in addition to that provided by milk and salivary IgA antibodies, may explain why breast-fed babies have less otitis media than formula-fed ones.

C-reactive protein (CRP) in early diagnosis of neonatal septicemia. Acta Paediatr Scand, 68: 825, 1979.-The usefulness of CRP in early detection of neonatal septicemia/meningitis and urinary tract infection was studied in a neonatal unit using a semiquantitative latex-agglutination as a rapid screening method, and electroimmuno assay as reference method for CRP determination. In 94 % of non-infected infants CRP was c 1 5 mg/l and 82 % had CRP <10 mg/l up to 3 days of age. After 3 days of age 96% had CRP <10 mg/l. The initial CRP level was increased in 16 out of 18 patients (89%) with bacterial septicemia. Low CRP was seen in one patient with total agranulocytosis and septicemia from Streptococcus type B and in one patient with Staphylococcus albus sepsis. A rise in CRP was also seen in very pre-term infants with septicemia. Increased initial CRP was uncommon in neonatal urinary tract infection (2 of 9), hut a rise was seen in 3 additional patients. A comparison between CRP, total neutrophil blood cell count and hand neutrophil count as diagnostic parameters was in favour of CRP at this early stage of infection. CRP is of definite value as an aid in early diagnosis of neonatal septicemia and bacterial meningitis.

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Feasibility studies originated earlier in this laboratory, on microwave energy thermal processing of foods, were continued. A means of measuring temperature distribution, as well as a photometric method for determining time/temperature integration within thermally processed foods, were developed. A knowledge of the processing parameters involved in the preservation of foods by microwave energy was obtained. Feasibility of the process was demonstrated.